U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress

U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress

U.S. Defense Infrastructure in the Indo-Pacific: June 6, 2023
Background and Issues for Congress
Luke A. Nicastro
The Indo-Pacific occupies a central role in U.S. national strategy and hosts a large
Analyst in U.S. Defense
number of U.S. military forces. To enable the operation of these forces and accomplish
Infrastructure Policy
its strategic objectives, the United States maintains and uses at least 66 significant

defense sites spread across the region. This defense infrastructure network performs and
supports numerous military functions, including basing for military personnel and

weapon systems; domain awareness and area defense; maintenance and repair; training and exercises, storage and
prepositioning of materiel; and research, development, testing, and evaluation activities. Some Indo-Pacific
installations are located in U.S. states, territories, or possessions (such as Hawaii and Guam); others are located in
allied or partner nations (such as South Korea and Japan). In addition to installations directly owned or operated
by the U.S. Department of Defense (DOD), the U.S. military also makes use of sites operated by allied or partner
nations (such as the Philippines and Australia).
DOD’s basing posture in the Indo-Pacific reflects in part the legacy of decisions made under the geopolitical and
technological conditions of the Cold War. Following the Obama administration’s announcement of a “pivot to
Asia,” the focus of U.S. strategy (and with it, regional defense infrastructure) shifted toward prevailing in
competition against peer or near-peer rivals—particularly the People’s Republic of China (PRC). Since 2011, the
United States has negotiated access to 12 new defense sites in the Philippines and Australia, constructed new
installations in Japan and Guam, and expanded facilities at dozens of existing installations across the region.
Congress’ role in these developments has included, for example, appropriating over $8.9 billion for new military
construction projects at Indo-Pacific sites since fiscal year (FY) 2020 and establishing infrastructure
improvements as an investment priority through the Pacific Deterrence Initiative (PDI).
Issues that Congress may consider include: (1) whether DOD’s current regional basing posture adequately
supports strategic goals and operational requirements, and (2) whether the construction, maintenance, and
utilization of defense infrastructure is appropriately resourced and managed. Within these issue areas, particular
questions that may be raised in the 118th Congress include:
• What criteria should inform the placement of U.S. bases in the Indo-Pacific, and what role should
Congress play in determining those criteria?
• How can DOD optimize the organization, operation, and resilience of its Indo-Pacific
installations, and what assessment and oversight options are available to Congress?
• What is an appropriate level of investment for military construction, facilities sustainment, and
related infrastructure activities?

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Contents
Introduction ..................................................................................................................................... 1
Background ..................................................................................................................................... 2
Defining Defense Infrastructure ................................................................................................ 2
Strategic and Operational Role ................................................................................................. 4
Infrastructure and National Strategy ................................................................................... 4
Infrastructure in a Contested Environment ......................................................................... 6
Current U.S. Basing Posture ............................................................................................................ 7
Geographic Overview ............................................................................................................. 10
East of the International Date Line .......................................................................................... 11
Alaska ................................................................................................................................ 11
Washington ....................................................................................................................... 12
California .......................................................................................................................... 12
Hawaii ............................................................................................................................... 12
West of the International Date Line ........................................................................................ 13
Wake Island ....................................................................................................................... 14
Guam and the Northern Mariana Islands .......................................................................... 14
The Marshall Islands, Micronesia, and Palau ................................................................... 14
Japan (Mainland) .............................................................................................................. 15
Japan (Okinawa) ............................................................................................................... 15
Republic of Korea ............................................................................................................. 16
The Philippines ................................................................................................................. 16
Singapore .......................................................................................................................... 16
Australia ............................................................................................................................ 17
British Indian Ocean Territory (Diego Garcia) ................................................................. 17
Other Indo-Pacific Sites .................................................................................................... 17
Issues for Congress ........................................................................................................................ 18
Indo-Pacific Basing Posture .................................................................................................... 18
Placement .......................................................................................................................... 18
Organization ...................................................................................................................... 24
Resilience .......................................................................................................................... 25
Resourcing Regional Defense Infrastructure .......................................................................... 26
Military Construction ........................................................................................................ 26
Facilities Sustainment, Restoration, and Modernization................................................... 29
Pacific Deterrence Initiative ............................................................................................. 30

Figures
Figure 1. The Indo-Pacific Region .................................................................................................. 2
Figure 2. U.S. Defense Sites in the Indo-Pacific ............................................................................. 9
Figure 3. U.S. Defense Sites, East of the International Date Line ................................................. 11
Figure 4. U.S. Defense Sites, West of the International Date Line ............................................... 13
Figure 5. Regional Missile Threat ................................................................................................. 20

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Tables
Table 1. Military Construction Appropriations, FY2020-23 ......................................................... 27

Table A-1. U.S. Defense Sites in the Indo-Pacific ......................................................................... 44

Appendixes
Appendix A. Key Sites and Facilities ............................................................................................ 32
Appendix B. Historical Overview of Indo-Pacific Defense Infrastructure ................................... 47

Contacts
Author Information ........................................................................................................................ 51

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U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress

Introduction
Encompassing the seas, islands, and littoral areas of the Pacific and Indian Oceans between the
western coast of North America and India (see Figure 1), the Indo-Pacific region hosts more than
375,000 U.S. military personnel using at least 66 distinct defense sites.1 The 2022 National
Security Strategy describes the Indo-Pacific as the “epicenter of 21st century geopolitics,” and the
2022 National Defense Strategy identifies attempts by the People’s Republic of China (PRC) to
“refashion the Indo-Pacific region” as part of “the most comprehensive and serious challenge to
U.S. national security.”2 Secretary of Defense Lloyd Austin has described Indo-Pacific defense
infrastructure as “provid[ing] us with the ability to position our troops forward in theater, so that
we can deter much further forward.”3
Given the role of defense infrastructure in undergirding U.S. military presence and power
projection in the region, Congress has devoted considerable attention to Indo-Pacific defense
infrastructure issues, and may choose to do so in the future. This report:
• defines the fundamental elements of infrastructure policy and basing posture;
• describes the historical development of Indo-Pacific defense infrastructure;
• characterizes the strategic and operational roles of Indo-Pacific defense sites;
• describes the current U.S. basing posture in Alaska, Washington, California,
Hawaii, Wake Island, Guam, the Northern Mariana Islands, the Marshall Islands,
Japan, the Republic of Korea, the Philippines, Singapore, Australia, and the
British Indian Ocean Territory (Diego Garcia); and
• analyzes selected issues for congressional consideration.4

1 The nomenclature and boundaries of the Indo-Pacific have changed over time. Previous presidential administrations
and Congresses have used the terms ‘Asia-Pacific,’ the ‘East Asia-Pacific’, and the ‘Asian Pacific Rim’ in reference to
regions which have sometimes excluded India and the west coast of North America. However, the 2022 Indo-Pacific
Strategy of the United States broadly describes the Indo-Pacific as “stretch[ing] from [North America’s] Pacific
coastline to the Indian Ocean,” and this report adopts this definition. Personnel figure from “About U.S.
INDOPACOM,” U.S. INDOPACOM, at https://www.pacom.mil/About-usindopacom/; installations figure from CRS
analysis of a variety of DOD documents, including the “FY2022 Base Structure Report.”
2 “National Security Strategy”, The White House, October 2022, p. 37, available at https://www.whitehouse.gov/wp-
content/uploads/2022/10/Biden-Harris-Administrations-National-Security-Strategy-10.2022.pdf; and “National
Defense Strategy”, Department of Defense, October 2022, p. 4. available at https://media.defense.gov/2022/Oct/27/
2003103845/-1/-1/1/2022-national-defense-strategy-npr-mdr.pdf.
3 Secretary Lloyd Austin, quoted in “House Appropriations Subcommittee on Defense Hearing on Fiscal Year 2024
Request for the Department of Defense,” March 23, 2023, available at
https://appropriations.house.gov/legislation/hearings/budget-hearing-fiscal-year-2024-request-department-defense.
4 All information in this report is derived from unclassified and publicly available sources.
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U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress

Figure 1. The Indo-Pacific Region

Source: “U.S. INDOPACOM Area of Responsibility,” https://www.pacom.mil/About-USINDOPACOM/
USPACOM-Area-of-Responsibility/
Notes: The continental United States, Canada, Mexico, and surrounding waters to a distance of 500 nautical
miles from shore fall within the U.S. Northern Command AOR. See https://www.northcom.mil/About.
Background
Defining Defense Infrastructure
Defense infrastructure consists of the buildings, permanent facilities, fixed systems, real property,
and related assets owned, operated, or used by a nation’s government for military purposes. For
DOD, the basic ‘unit’ of infrastructure is the installation, defined statutorily as any “base, camp,
post, station, yard, center, or other activity under the jurisdiction…[or] operational control of the
Secretary of a military department or the Secretary of Defense.”5 An installation or group of
installations may serve as a base, which DOD defines as “a locality from which operations are
projected or supported.”6 DOD classifies its overseas bases into two categories: enduring

5 Title 10, United States Code §2801. Available at https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-
title10-section2801&num=0&edition=prelim.
6 DOD also offers two additional definitions for base: 1) “An area or locality containing installations which provide
logistics or other support”; 2) “Home airfield or home carrier”. See DOD Dictionary of Military and Associated Terms,
Department of Defense, February 2023, p. 21.
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locations, which support ongoing activities and interests on a permanent basis; and contingency
locations, which provide temporary support for contingency operations.7
Each military department (MILDEP) manages its infrastructure through its own organizational
structures, policies, and programs, while the Under Secretary of Defense for Acquisition and
Sustainment sets policy and exercises oversight of infrastructure-related matters across DOD.8
The construction of new facilities is funded through Military Construction (MILCON)
appropriations, while other infrastructure-related functions such as facilities sustainment,
restoration, and modernization (FSRM) and base operations are funded through Operation and
Maintenance (O&M) appropriations.
Within the Indo-Pacific region, this report identifies and describes 66 military bases. Of these, 26
are located to the east of the International Date Line (IDL), and 40 are located to the west of the
IDL (see Figure 2). The majority of sites are within the U.S. Indo-Pacific Command
(INDOPACOM) Area of Responsibility (AOR); also included are select locations in Alaska,
Washington, and California that fall within the U.S. Northern Command (NORTHCOM) AOR
but are located in the Indo-Pacific region as defined above and provide substantial support for
regionally focused operations.
Defense infrastructure in the Indo-Pacific performs or supports an array of military functions,
including:
• Basing of personnel and weapons systems. The most fundamental function of
military installations is to provide space for servicemembers, weapons systems,
and the resources necessary for their operation (e.g., food, fuel, munitions).
Installations serve as work sites during both peacetime and wartime, enabling
activities ranging from routine office work to launching combat missions. Larger
installations often include housing for defense personnel and dependents, as well
as morale, welfare and recreation (MWR) facilities.
• Domain awareness and area defense. Beyond their role in hosting combat
forces, fixed sites and facilities play a key role in detecting and countering threats
to U.S. and allied forces and territory. Elements of Indo-Pacific defense
infrastructure performing or supporting this mission include radar sites intended
to detect incoming missiles or aircraft (e.g., Shariki Communications Site, Japan)
and ground-based interceptor sites intended to neutralize incoming missiles (e.g.,
Ft. Greely, AK).9
• Maintenance and repair. The complexity of major weapons systems often
requires specialized facilities and equipment to conduct maintenance, repair, and
overhaul activities. These may include vehicle maintenance facilities, aircraft
maintenance hangars, and naval shipyards. Examples of Indo-Pacific facilities
performing maintenance and repair functions include the U.S. Naval Ship Repair

7 Enduring locations are categorized based on the degree of U.S. presence and include main operating bases, forward
operating sites, and cooperative security locations; contingency locations are categorized by intended use period and
include initial (immediate need), temporary (1-24 months), and semipermanent (24-60 months) locations. See “Joint
Publication 4-04, Contingency Basing,” Chairman of the Joint Chiefs of Staff, January 2019, pp. vii-ix. Available at
https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp4_04.pdf.
8 For more information on installation management, see CRS In Focus IF11263, Defense Primer: Military Installations
Management.
9 See Jason Cutshaw, “Shariki Soldiers Defend Homeland, Allies,” U.S. Army, October 8, 2019, at
https://www.army.mil/article/227673/shariki_soldiers_defend_homeland_allies and “U.S. Army Garrison Alaska – Fort
Greely,” updated July 5, 2022, at https://home.army.mil/alaska/index.php/fort-greely.
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U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress

Facility and Japan Regional Maintenance Center (part of Fleet Activities
Yokosuka and Fleet Activities Sasebo, Japan).10
• Training and exercises. U.S. and allied forces rely on regional training and
exercise areas to maintain and enhance readiness, test operational plans and
concepts, and demonstrate and improve interoperability. Examples of Indo-
Pacific sites used for training and exercises include the Jungle Warfare Training
Center at Camp Gonsalves in Okinawa, Japan and the Black Rapids Training Site
in Black Rapids, AK.11
• Storage, prepositioning, and distribution of equipment and supplies. To
ensure logistical preparedness and enable rapid contingency responses, the U.S.
military stores equipment and supplies at locations across the Indo-Pacific. These
stocks are maintained in a variety of ways, including aboard regionally based
maritime prepositioning ships (such as those homeported in Diego Garcia) and at
facilities such as the Defense Logistics Agency’s Distribution Yokosuka in
Japan.12
• Research, development, test, and evaluation (RDT&E). DOD uses a number
of Indo-Pacific sites to develop and test new technologies and weapon systems,
especially those requiring large amounts of air or ocean space. Examples of
major RDT&E sites in the region include the Pacific Missile Range Facility,
Barking Sands in Hawaii and the Ronald Reagan Ballistic Missile Defense Test
Site in the Marshall Islands.13
Strategic and Operational Role
Infrastructure and National Strategy
A review of planning and policy documents issued by the White House and the Department of
Defense since 2020 illustrates the importance of Indo-Pacific defense infrastructure to
contemporary U.S. strategy. The 2021 Global Posture Review identified a need to “seek greater
regional access for military partnership activities” and “enhance infrastructure in Australia and
the Pacific Islands” to accomplish DOD’s goals of “contribut[ing] to regional stability and
deter[ring] potential Chinese military aggression and threats from North Korea.”14 The 2022
Indo-Pacific Strategy articulates four security-related U.S. objectives in the region: advancing a
free and open region, building connections to and among regional partners, bolstering regional

10 See “U.S. Naval Ship Repair Facility and Japan Regional Maintenance Center,” U.S. Navy, at
https://www.srf.navy.mil/.
11 See “Jungle Warfare Training Center,” 3rd Marine Division, at https://www.3rdmardiv.marines.mil/Units/Jungle-
Warfare-Training-Center/ and Staff Sgt. Christopher Dennis, “Northern Warfare Training Center preparing Soldiers to
become Arctic Experts,” U.S. Army, November 24, 2021 at https://www.army.mil/article/252226/northern_warfare_
training_center_preparing_soldiers_to_become_arctic_experts.
12 See “Maritime Prepositioning Ships,” U.S. Navy, updated October 13, 2021, at https://www.navy.mil/Resources/
Fact-Files/Display-FactFiles/Article/2223033/maritime-prepositioning-ships-t-ak-t-akr-and-t-aot/ and “DLA
Distribution Yokosuka,” Defense Logistics Agency, at https://www.dla.mil/Distribution/Locations/Yokosuka/.
13 See “Pacific Missile Range Facility Barking Sands,” Commander, Navy Region Hawaii, at
https://cnrh.cnic.navy.mil/Installations/PMRF-Barking-Sands/ and “Ronald Reagan Ballistic Missile Defense Test Site
Fact Sheet,” U.S. Army Space and Missile Defense Command Public Affairs, at https://www.smdc.army.mil/Portals/
38/Documents/Publications/Fact_Sheets/RTS.pdf.
14 “DOD Concludes 2021 Global Posture Review,” Department of Defense, November 29, 2021, at
https://www.defense.gov/News/Releases/Release/Article/2855801/dod-concludes-2021-global-posture-review/.
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security, and building resilience to transnational threats.15 Both the 2022 National Security
Strategy (NSS) and National Defense Strategy (NDS) characterize PRC attempts to reshape the
Indo-Pacific and the broader international order as the most acute military threat to U.S. interests,
and DOD officials have stated in congressional testimony that “a Taiwan contingency is the
pacing scenario” for U.S. planners.16 The NSS identifies a “strong and consistent defense
presence” as a key contributor to regional peace and stability, while the NDS states that DOD will
“reinforce and build out a resilient security architecture in the Indo-Pacific region.”17 The NDS
also identifies the following four “top-level defense priorities.”
• Defending the homeland, paced to the growing multi-domain threat posed by
the PRC.
• Deterring strategic attacks against the United States, allies, and partners.
• Deterring aggression, while being prepared to prevail in conflict when necessary.
• Building a resilient Joint Force and defense ecosystem.18
Although only the Global Posture Review explicitly mentions defense infrastructure, the Indo-
Pacific Strategy, NSS, and NDS all emphasize the strategic centrality of a sustained, significant
forward U.S. military presence; such a presence would rely heavily on a network of regional
defense sites. The six broad functions of Indo-Pacific infrastructure described above—basing of
personnel and weapons systems, domain awareness and area defense, maintenance and repair,
support for training and exercises, storage, prepositioning, and distribution of equipment and
supplies, and support for RDT&E activities—are essential enablers of the regional presence and
operation of the U.S. military. This is especially true for naval and air forces, which require
extensive and specialized facilities for storage, operation, maintenance, and repair.
Indo-Pacific defense infrastructure also supports the four top-level defense priorities identified in
the NDS. Sites in Japan, Alaska, California, and elsewhere host detection and defense capabilities
intended to protect the U.S. homeland from both conventional and nuclear attack. To deter
strategic attacks on the United States or its allies, DOD relies on Indo-Pacific sites to enable the
“forward deployment of strategic bombers, dual-capable fighter aircraft, and nuclear weapons to
region and globally… including ballistic missile submarine port visits and strategic bomber
missions.”19 A robust regional basing posture may also help deter aggression by signaling
enduring U.S. commitment to the region. Alternatively, some analysts have suggested that a large
U.S. military footprint may intensify the security dilemma and thus make aggressive state
behavior more likely).20 Finally, the scale and diversity of functions performed or supported by

15 “Indo-Pacific Strategy of the United States,” The White House, February 2022, p. 7, at https://www.whitehouse.gov/
wp-content/uploads/2022/02/U.S.- Indo-Pacific-Strategy.pdf.
16 “Senate Foreign Relations Committee Hearing on the Future of U.S. Policy on Taiwan,” December 8, 2021, p. 10.
Committee print available at https://www.congress.gov/117/chrg/CHRG-117shrg47712/CHRG-117shrg47712.pdf.
17 “2022 National Security Strategy”, p. 38 https://www.whitehouse.gov/wp-content/uploads/2022/10/Biden-Harris-
Administrations-National-Security-Strategy-10.2022.pdf and 2022 National Defense Strategy, p. 14
https://media.defense.gov/2022/Oct/27/2003103845/-1/-1/1/2022-NATIONAL-DEFENSE-STRATEGY-NPR-
MDR.PDF
18 “2022 National Defense Strategy”, Department of Defense, October 2022 p. 7. Available at
https://media.defense.gov/2022/oct/27/2003103845/-1/-1/1/2022-national-defense-strategy-npr-mdr.pdf .
19 “2022 Nuclear Posture Review,” Department of Defense, October 2022, p. 15. Available at
https://media.defense.gov/2022/oct/27/2003103845/-1/-1/1/2022-national-defense-strategy-npr-mdr.pdf
20 For one interpretation of the role of overseas bases in deterring adversaries and assuring allies, see Raphael Cohen,
“Why Overseas Bases Continue to Make Sense for the U.S.,” War on the Rocks, January 14, 2021, available at
https://warontherocks.com/2021/01/why-overseas-military-bases-continue-to-make-sense-for-the-united-states/. For
more on basing and the security dilemma, see “Placement” in the “Issues for Congress” section of this report.
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Indo-Pacific defense infrastructure contributes to the broader priority of “building a resilient Joint
Force and broader defense ecosystem.”21
Infrastructure in a Contested Environment
The operational role of defense infrastructure is susceptible to change should significant
geopolitical shifts occur. Under current peacetime conditions, concentrating infrastructure near
operational areas can yield a number of advantages. Clustering military facilities in a smaller
number of sites is cheaper and creates organizational and logistical efficiencies, while locating
bases near operational areas shortens transit and allows units to spend more time on station (this
is particularly important for aircraft, given their range limitations).22
However, in the event of a conflict between the United States and a regional power with
significant air and missile capabilities, this same concentration and proximity would expose U.S.
forces and facilities west of the International Date Line—especially those within the First and
Second Island Chains—to a higher likelihood of successful adversary attack. Some analysts argue
the most acute threat to U.S. infrastructure in the Indo-Pacific stems from the PRC’s missile
capabilities, which the DOD’s 2022 Missile Defense Review characterizes in the following
manner:
Over the past two decades, the PRC has dramatically advanced its development of
conventional and nuclear-armed ballistic and hypersonic missile technologies and
capabilities, through intense and focused investment, development, testing, and
deployments… In many areas such as conventional ballistic and hypersonic missile
technologies, the PRC continues to close the gap with the United States, and will likely
continue to develop and expand its missile capabilities. Increasingly sophisticated and
proliferated space-based Intelligence, Surveillance, and Reconnaissance (ISR) networks,
and improved Command and Control (C2) systems, have greatly improved the precision
and accuracy of missile systems the PRC would employ to deter and counter U.S. forward
presence and operations, especially in the Western Pacific region.23
Although North Korean air and missile strike capabilities are considerably less developed than
those of the PRC, DOD assesses that “North Korea continues to improve, expand, and diversify
its conventional and nuclear missile capabilities, posing an increasing risk to the U.S. homeland
and U.S. forces in theater, as well as regional allies and partners.”24
To meet the demands of a contested environment, the Air Force, Army, Navy, and Marine Corps
have all developed concepts for more distributed and diversified combat and logistical operations.
The Air Force’s Agile Combat Employment (ACE), the Army’s Multi-Domain Operations
(MDO), the Navy’s Distributed Maritime Operations (DMO), and the Marine Corps’
Expeditionary Advanced Basing Operations (EABO) all represent attempts to reduce the
vulnerability of air, naval, and ground forces and increase their effectiveness against an adversary
able to credibly disrupt, contest, or deny U.S. control of the battlespace.25 Although some aspects

21 “2022 National Defense Strategy”, p. 7.
22 For a more detailed discussion of aircraft range and basing considerations, see “Placement” in the “Issues for
Congress” section of this report.
23 “2022 Missile Defense Review,” Department of Defense, October 2022, p. 2. Available at https://media.defense.gov/
2022/Oct/27/2003103845/-1/-1/1/2022-national-defense-strategy-npr-mdr.pdf.
24 Ibid., p. 3.
25 For an analysis of regional ground forces that includes a more comprehensive description of the Army’s role, see
CRS Report R47096, U.S. Ground Forces in the Indo-Pacific: Background and Issues for Congress, by Andrew
Feickert.
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of these three concepts are globally applicable, they are particularly oriented around potential
Indo-Pacific contingencies.
These distributed operational concepts represent a break from previous planning paradigms, and
will make accordingly different use of defense infrastructure. The most radical change may come
in the air domain. The Air Force describes ACE as a means of “shift[ing] operations from
centralized physical infrastructures to a network of smaller, dispersed locations that can
complicate adversary planning and provide more options for joint force commanders.”26 Some
analysts have characterized this as a ‘hub-and-spokes’ approach, with an enduring location (e.g.,
an existing U.S. or allied airbase) serving as a hub for a number of contingency locations (e.g.,
civilian airports) between which aircraft can be shifted and from which sorties may be launched.27
Although the infrastructure implications of the Army’s MDO and the Navy’s DMO are less
sweeping, both entail decreasing the concentration of logistics and supply infrastructure. As part
of MDO, the Army seeks to “disperse deployment and sustainment,” partly through “dispersed
supply nodes operated by forward presence units;” while the Navy’s vision of a larger, more
dispersed fleet operating over a wider area could increase the need for forward, distributed
logistics and maintenance sites (including what the Navy terms “distributed expeditionary shore
infrastructure” to provide forward damage repair, mobile construction, cargo handling, and
medical services).28 From a ground forces perspective, the Marine Corps’ EABO similarly
envisions the “employment of mobile, low-signature, persistent… naval expeditionary forces
from a series of austere, temporary locations ashore or inshore within a contested or potentially
contested maritime area.”29 Given the novel character of these operational concepts, their
implementation may carry significant implications for regional basing posture, resourcing, and
management.
Current U.S. Basing Posture
Within the Indo-Pacific region, the United States currently utilizes at least 66 significant defense
sites spread across four U.S. states, three U.S. territories, eight countries, and one British overseas
territory (see the map of U.S. defense sites provided in Figure 2 below; a more detailed
description of each regional defense site is also provided in the Appendix A). These sites include:
• installations that are owned and operated by DOD (this arrangement is the norm
in U.S. states and territories);
• installations that are operated by DOD but located in host nations (this
arrangement is the norm in South Korea, Japan, and the British Indian Ocean
Territory); and

26 See “Agile Combat Employment,” U.S. Air Force, pp. 3-4, at https://www.doctrine.af.mil/portals/61/documents/
afdn_1-21/afdn%201-21%20ace.pdf .
27 See Patrick Mills, et al., Building Agile Combat Support Competencies to Enable Evolving Adaptive Basing
Concepts, (Santa Monica: RAND Corporation, 2020), p. 23, available at https://www.rand.org/content/dam/rand/pubs/
research_reports/rr4200/rr4200/rand_rr4200.pdf.
28 See “The U.S. Army in Multi-Domain Operations 2028,” U.S. Army Training and Doctrine Command, December 6,
2018, p. 37, at https://www.army.mil/article/243754/the_u_s_army_in_multi_domain_operations_2028; and “CNO
Releases Navigation Plan 2022,” U.S. Navy Press Release, July 26, 2022, p. 10, available at https://media.defense.gov/
2022/jul/26/2003042389/-1/-1/1/navigation%20plan%202022_signed.pdf
29 See Tentative Manual for Expeditionary Advanced Base Operations, Department of the Navy, Headquarters, U.S.
Marine Corps, February 2021, pp. 1-3 and 1-4. Available at https://mca-marines.org/wp-content/uploads/tm-eabo-first-
edition-1.pdf.
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• installations that are used by DOD but owned and operated by host nations (this
arrangement is the norm in the Philippines, Singapore, and Australia).
Some analysts and policymakers also divide regional defense sites between those located east of
the International Date Line (i.e., bases in Alaska, Washington, California, and Hawaii) and those
located west of the International Date Line.30 This division is analytically useful because sites
west of the International Date Line (IDL) may be within range of adversaries’ conventional strike
capabilities and would likely be used to directly support forward combat operations in a
contingency, while those east of the IDL would likely be less susceptible to opponents’
conventional strike capabilities.31 Moreover, because the majority of sites west of the IDL are
located outside of the United States, their use entails diplomatic and management considerations
(e.g., relations with host nation governments, the applicability of foreign legal regimes to land
use) that do not exist for sites east of the IDL.

30 See, for instance, the language establishing the Pacific Deterrence Initiative, which directs that activities improve
force design and posture “primarily west of the International Date Line.” Section 1251, William M. (Mac) Thornberry
FY2021 National Defense Authorization Act (P.L. 116-283).
31 For more on the ranges and capabilities of adversary weapons, see discussion under “Placement” in the “Issues for
Congress” section of this report.
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Figure 2. U.S. Defense Sites in the Indo-Pacific

Source: CRS graphic based on analysis of DOD information, including the “FY2022 Base Structure Report,” installation and unit web pages, and related documentation.
Notes: Naval Communications Station Harold E. Holt (located near Exmouth, Australia) is not depicted due to space constraints.

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U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress

Geographic Overview
Most of the Indo-Pacific region falls within the U.S. INDOPACOM AOR. This COCOM
accordingly exercises oversight and theater-level direction over the strategic and operational
functions of theater infrastructure (installations located in Alaska, Washington, and California fall
within the U.S. NORTHCOM AOR).
All of DOD’s uniformed service branches operate installations in the region. The Army, Navy,
Marine Corps, and Air Force operate installations in the INDOPACOM AOR.
Major Army installations are mainly concentrated in Alaska, Washington, Hawaii, South Korea,
Japan, and the Republic of the Marshall Islands. These installations provide basing for ground
units, missile detection and defense capabilities, and facilities for training, exercises, RDT&E
activities, and logistical support.
Major Navy installations are concentrated in Washington, California, Hawaii, Guam, Japan, and
Diego Garcia. These installations provide basing and maintenance and repair capabilities for
ships and aircraft, as well as facilities for training, exercises, RDT&E activities, and logistical
support. Major Marine Corps installations are concentrated in California, Hawaii, Guam, and
Japan. These installations provide basing for ground units and aircraft as well as facilities for
training, exercises, and logistical support.
Major Air Force installations are concentrated in Alaska, Washington, California, Hawaii, Guam,
South Korea, and Japan. These installations provide aircraft basing and maintenance and repair
capabilities, missile detection and defense capabilities, and facilities for logistical support. Space
Force installations are located in Alaska and California. These installations provide space domain
awareness, missile detection and defense, and space launch capabilities.
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East of the International Date Line
This report identifies 26 bases east of the IDL that support Indo-Pacific defense functions (see
Figure 3 below).
Figure 3. U.S. Defense Sites, East of the International Date Line

Source: CRS graphic based on analysis of DOD information, including the “FY2022 Base Structure Report,”
installation and unit web pages, and related documentation.
Notes: Given space and scope constraints, this map, and the Appendix – Key Sites and Facilities, does not
include several major installations located in California (e.g., Edwards AFB) because their functions are not
directly or specifically oriented around support for operations in the Indo-Pacific theater.
Alaska
Alaska hosts Indo-Pacific-focused Army, Air Force, and Space Force installations, including Fort
Wainwright, Joint Base Elmendorf-Richardson, Eielson Air Force Base, and Clear Space Force
station. These sites are used to base Army ground units (including the headquarters of the 11th
Airborne Division and two of its combat brigades), Army aviation units (including two aviation
battalions and Air Force aircraft (including fighter, command and control, and airlift squadrons).
DOD also uses defense infrastructure in Alaska to detect and intercept missile threats to the
continental United States and provide specialized training for cold weather and mountain
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environments.32 Several open source press reports have also highlighted the role smaller Alaskan
airfields may play in a regional contingency.33
Washington
Washington hosts Indo-Pacific-focused Army, Navy, and Air Force installations, including Joint
Base Lewis-McChord, Naval Base Kitsap, and Fairchild Air Force Base. These sites are used to
base Army units (including the 7th Infantry Division), Navy vessels (including two aircraft
carriers, three submarine squadrons, and seven destroyers), and Navy and Air Force aircraft
(including Navy electronic attack, maritime patrol, and reconnaissance squadrons and Air Force
airlift and refueling squadrons). DOD also uses defense infrastructure in Washington to maintain
and repair naval vessels, store and maintain submarine-based nuclear weapons, store and
distribute fuel, and train ground and air units.34
California
California hosts Indo-Pacific-focused Navy, Marine Corps, Air Force, and Space Force
installations, including Naval Base San Diego, Marine Corps Base Camp Pendleton, Travis Air
Force Base, and Vandenberg Space Force Base. These sites are used to base Navy vessels and
specialized units (including most of the Naval Surface Force, U.S. Pacific Fleet, one submarine
squadron, four Sea-Air-Land (SEAL) teams, and the 30th Naval Construction Regiment), Marine
Corps ground units (including the 1st Marine Division and the 1st Marine Logistics Group), Navy,
Marine Corps, and Air Force aircraft (including: Navy fighter, command and control, and
helicopter squadrons; Marine Corps fighter, tiltrotor, and helicopter squadrons; and Air Force
reconnaissance, refueling, and airlift squadrons), and a Space Force Delta. DOD also uses defense
infrastructure in California for training and large-scale RDT&E activities, to conduct space
launches, and provide ballistic missile defense.35
Hawaii
Hawaii hosts Army, Navy, Marine Corps, and Air Force installations, including Schofield
Barracks, Joint Base Pearl Harbor-Hickam, and Marine Corps Base Hawaii. These sites are used
to base Army ground units (including the 25th Infantry Division), Navy vessels (including
destroyers, cruisers, and attack submarines), Marine Corps ground units (including the 3rd Marine
Littoral Regiment), and Marine Corps, and Air Force aircraft (including Air Force fighter and
airlift squadrons and Marine Corps helicopter, tiltrotor, and UAV squadrons). DOD also uses sites
in Hawaii to conduct training and large-scale RDT&E activities and store and distribute fuel.36
Defense infrastructure in Hawaii has been the subject of attention from policymakers and analysts
in part because of a highly publicized leak from the Red Hill Bulk Fuel Facility in November
2021. Subsequent to the reported leak and defueling plan, the condition of facilities in the state

32 For more information and sources, see Appendix A – Key Sites and Facilities, “Alaska.”
33 See Tyler Rogoway, “Special Ops Train To Defend Strategic Aleutian Islands Radar Outpost During All-Out War,”
The Drive, October 18, 2021, at https://www.thedrive.com/the-war-zone/42783/special-ops-train-to-defend-strategic-
radar-outpost-in-the-aleutian-islands-during-all-out-war and David Axe, “The U.S. Air Force has a Base Right Next to
Russia,” Forbes, October 23, 2021, at https://www.forbes.com/sites/davidaxe/2021/10/23/the-us-air-force-has-a-base-
right-next-to-russia-it-just-sent-f-16s-to-visit/
34 For more information and sources, see Appendix A – Key Sites and Facilities, “Washington.”
35 For more information and sources, see Ibid., “California.”
36 For more information and sources, see Ibid., “Hawaii.” Hawaii’s fuel storage functions are currently undergoing
major shifts as the Red Hill Bulk Storage Facility is defueled (see “Red Hill Bulk Fuel Storage Site in Hawaii,”
Environmental Protection Agency, at https://www.epa.gov/red-hill).
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has featured in a November 2022 report on Army infrastructure by the Congressional Budget
Office (CBO).37
West of the International Date Line
This report identifies 40 bases west of the IDL that support Indo-Pacific defense functions (see
Figure 4 below).
Figure 4. U.S. Defense Sites, West of the International Date Line

Source: CRS graphic based on analysis of DOD information, including the “FY2022 Base Structure Report,”
installation and unit web pages, and related documentation.
Notes: Naval Communications Station Harold E. Holt is not depicted due to space constraints.

37 CBO assessed the Army’s deferred maintenance backlog and found that “Fort Bragg in North Carolina and U.S.
Army Garrison Hawaii accounted for significantly higher amounts of deferred maintenance costs than other Army
bases.” See “The Army’s Costs to Eliminate Its Deferred Maintenance Backlog and to Renovate and Modernize Its
Buildings,” Congressional Budget Office, November 2022, p. 11, available at https://www.cbo.gov/publication/58830.
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Wake Island
Wake Island (an unincorporated U.S. territory) hosts Wake Island Airfield, an Air Force
installation that supports trans-Pacific military air traffic as well as missile test activities.38
Guam and the Northern Mariana Islands
Guam (an unincorporated U.S. territory) hosts Navy, Marine Corps, and Air Force installations,
including Naval Base Guam, Marine Corps Base Camp Blaz, and Andersen Air Force Base (all
managed jointly as Joint Region Marianas). These sites are used to base Army and Marine Corps
ground units (including an Army Terminal High Altitude Area Defense Battery and future Marine
ground units), Navy vessels (including one submarine squadron), and rotational deployments of
Air Force bomber aircraft.39 Since 2011, Guam has attracted a considerable amount of attention
from policymakers and analysts as a strategic hub for U.S. military operations in the Indo-Pacific.
DOD’s infrastructure investments have undergone a significant increase over the past decade.40
The Northern Mariana Islands (a U.S. commonwealth and unincorporated territory) hosts a
number of sites that are used to support training and exercise activities, including the Marianas
Island Range Complex and Tinian International Airport.41 DOD is also constructing new
infrastructure to allow increased usage of the Northern Mariana Islands in support of ACE and
related requirements.42
The Marshall Islands, Micronesia, and Palau
The Marshall Islands, Micronesia, and Palau (commonly referred to as the Compacts of Free
Association, or COFA, states) host an Army installation used for missile defense-focused RDT&E
activities (Army Garrison-Kwajalein Atoll) and a site to support the planned installation of an Air

38 For more information and sources, see Appendix A – Key Sites and Facilities, “Wake Island.”
39 For more information and sources, see Appendix A – Key Sites and Facilities, “Guam and the Northern Marianas.”
40 See “Congress funds the establishment and sustainment of defense infrastructure through the
Military Construction and Operation and Maintenance appropriations titles. In addition,
beginning in FY2021, Congress has authorized a particular set of Indo-Pacific defense
infrastructure appropriations as part of the Pacific Deterrence Initiative (PDI), a group of
regionally-focused defense investments and activities typically included as part of the annual
National Defense Authorization Act (NDAA).
Military Construction” in the “Issues for Congress” section of this report.
41 See reporting on recent military exercises on Tinian in Damien Cave, “An Anxious Asia Arms for a War It Hopes to
Prevent,” New York Times, March 25, 2023 and Chris Gordon, “F-22s Deploy to Tinian for First Time as Part of ACE
Exercise,” Air & Space Forces Magazine, March 3, 2023 at https://www.airandspaceforces.com/photos-f-22s-deploy-
to-tinian-for-first-time-as-part-of-ace-exercise/.
42 In FY2023, Congress appropriated approximately $150 million for military construction in the
Northern Mariana Islands. See “Congress funds the establishment and sustainment of defense
infrastructure through the Military Construction and Operation and Maintenance appropriations
titles. In addition, beginning in FY2021, Congress has authorized a particular set of Indo-Pacific
defense infrastructure appropriations as part of the Pacific Deterrence Initiative (PDI), a group of
regionally-focused defense investments and activities typically included as part of the annual
National Defense Authorization Act (NDAA).
Military Construction” in the “Issues for Congress” section of this report.
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Force radar system.43 Some defense analysts and policymakers hold that the importance of the
COFA states is increasing, due to their strategic location and potential to support U.S. capabilities
in the event of a regional contingency.44
Japan (Mainland)
Mainland Japan hosts Army, Navy, Marine Corps, and Air Force installations, including Camp
Zama, Fleet Activities Yokosuka, Marine Corps Air Station Iwakuni, and Yokota Air Base. These
sites are used to base and support Army ground and aviation units, Navy vessels (including an
aircraft carrier, destroyers, cruisers, and amphibious assault ships), and Navy, Marine Corps, and
Air Force fighter, electronic attack, command and control, tanker, and airlift aircraft. DOD also
uses defense infrastructure in mainland Japan to detect and intercept missile threats, maintain and
repair surface warships and submarines, and conduct training and exercises. 45
Japan (Okinawa)
Okinawa is a Japanese prefecture consisting of approximately 49 inhabited islands located about
400 miles southwest of mainland Japan.46 It hosts Army, Marine Corps, and Air Force
installations, including Army Garrison Okinawa, Marine Corps Base Camp Butler, and Kadena
Air Base. These sites are used to base and support Marine Corps units (including the III Marine
Expeditionary Force) and Marine Corps and Air Force fighter, tilt-rotor, rotary wing, airlift, and
aerial refueling aircraft. DOD also uses sites on Okinawa to conduct training and exercises
specific to jungle environments and support fuel storage and distribution functions.47 DOD
installations on Okinawa also represent the closest U.S.-operated bases to Taiwan and the South
China Sea, both possible operational areas in a potential conflict with the PRC.48
According to the Okinawan Prefectural Government, as of 2018 approximately 70% of the “areas
exclusively used by U.S. forces” in Japan were located on Okinawa.49 The large U.S. defense
infrastructure footprint on Okinawa has generated significant controversy among sections of the
Okinawan public, and—pursuant to an agreement between the U.S. and Japanese governments—

43 The Compacts of Free Association establish relationships between these three nations and the United States. They
provide for, among other things, U.S. responsibilities for COFA states’ external defense and the establishment of U.S.
military bases within COFA states’ territories. For more information on the COFA relationships, see CRS In Focus
IF12194, The Compacts of Free Association, by Thomas Lum. For more information and sources on defense
infrastructure, see Appendix A – Key Sites and Facilities, “Marshall Islands, Micronesia, and Palau.”
44 See, for instance, Angela Smith, “US Compacts of Free Association Are Key to Deterring a Taiwan Contingency,”
The Diplomat, August 9, 2022 at https://thediplomat.com/2022/08/us-compacts-of-free-association-are-key-to-
deterring-a-taiwan-contingency/ and Jay Price, “As its relationship with China worsens, the US is making deals with
smaller Pacific nations,” KPBS, March 13, 2023, at https://www.kpbs.org/news/national/2023/03/13/relationship-china-
worsens-us-making-deals-smaller-pacific-nations .
45 For more information and sources, see Appendix A – Key Sites and Facilities, “Japan (Mainland).”
46 The Okinawan Prefectural Government reports that the prefecture spans 563,647 acres, representing only 0.6% of
Japan’s total land area.
47 For more information and sources, see Appendix A – Key Sites and Facilities, “Japan (Okinawa).”
48 From an operational perspective, this is particularly important for the employment of air power. See discussion in
“Placement” in the “Issues for Congress” section of this report.
49 “What Okinawa Wants You to Understand about the U.S. Military Bases,” Okinawa Prefectural Government, March
2018, available at https://dc-office.org/wp-content/uploads/2018/03/E-all.pdf.
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DOD is in the process of shifting thousands of Marines from bases in Okinawa to Guam’s Marine
Corps Camp Blaz.50
Republic of Korea
The Republic of Korea (ROK; also referred to as South Korea) hosts Army, Navy, Marine Corps,
and Air Force installations, including Camp Humphreys, Fleet Activities Chinhae, Marine Corps
Installation Camp Mujuk, and Osan Air Base. These sites are used to base and support Army units
(including the 2nd Infantry Division/ROK-U.S. Combined Division) and Air Force fighter,
reconnaissance, and attack aircraft. As noted above, following a 2004 bilateral agreement
between the ROK and U.S. governments, DOD installations are mainly concentrated around two
‘hubs’: the first centers on the city of Pyeongtaek and includes Camp Humphreys and Osan Air
Base, while the second centers on Daegu and includes USAG-Daegu, Fleet Activities Chinhae,
and MCI Camp Mujuk.51 Unlike in other locations west of the IDL, U.S. basing posture in South
Korean is primarily organized around deterring and resisting potential DPRK aggression.
The Philippines
The Philippines allows the U.S. DOD to deploy military forces at nine Philippine defense sites
spread across the country. This access is governed by the Enhanced Defense Cooperation
Agreement (EDCA), a bilateral agreement between the Philippines and the United States initially
signed in 2014 and expanded in 2023.52 Per the EDCA text, U.S. access is authorized “on a
rotational basis, as mutually determined;” authorized activities U.S. forces may conduct include
“security cooperation exercises; joint and combined training activities; humanitarian assistance
and disaster relief activities; and such other activities as may be agreed upon.”53 The increasing
U.S. defense presence in the Philippines has generated some controversy among the Philippine
public and certain elected officials (particularly the extent to which it is perceived to be directed
against the PRC).54
Singapore
Singapore allows the U.S. DOD to maintain a small presence known as Navy Region Center
Singapore primarily to provide logistical support for visiting surface warships. This access is
governed by the 1990 Memorandum of Understanding Regarding United States Use of Facilities
in Singapore, a bilateral agreement between Singapore and the United States initially signed in

50 See “Agreement between the Government of Japan and the Government of the United States of America Concerning
the Implementation of the Relocation of III Marine Expeditionary Force Personnel and Their Dependents From
Okinawa to Guam,” 2009, available at https://www.mofa.go.jp/region/n-america/us/security/agree0902.pdf. See also
CRS In Focus IF10672, U.S. Military Presence on Okinawa and Realignment to Guam. For a recent press report
covering this dynamic, see Rachel Oswald, “As China threatens Taiwan, Okinawa braces for war,” Roll Call, October
19, 2022, at https://rollcall.com/2022/10/19/as-china-threatens-taiwan-okinawa-braces-for-war/.
51 See p. 8 in the “Error! Reference source not found.” section of this report. Terence Roehrig, “South Korea: An A
lliance in Transition,” in Lord and Erickson (ed.) Rebalancing U.S. Forces, pp.74-75. For more information and
sources, see Appendix A – Key Sites and Facilities, “Republic of Korea.”
52 For more information and sources, see Appendix A – Key Sites and Facilities, “The Philippines.”
53 “Agreement between the Government of the United States of America and the Government of the Republic of the
Philippines on Enhanced Defense Cooperation,” signed April 28, 2014, available at https://www.state.gov/wp-content/
uploads/2019/02/14-625-Philippines-Defense-Cooperation.pdf.
54 See, for instance, Richard Heydarian, “U.S.-Philippines Defence Cooperation Hits Turbulence Amid Domestic
Opposition,” South China Morning Post, April 10, 2023, at https://www.scmp.com/comment/opinion/article/3216217/
us-philippines-defence-cooperation-hits-turbulence-amid-domestic-opposition. See also further discussion in the
“Placement” subsection of this report’s “Issues for Congress” section.
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1990 and renewed in 2019.55 Changi Naval Base and Sembawang shipyard are the largest
Singaporean support facilities to which the U.S. Navy has access, while Paya Lebar Air Base
hosts rotational U.S. Air Force personnel and aircraft.56
Australia
Australia allows the U.S. DOD to rotationally deploy a number of ground and air forces to bases
within the country, including a rotational U.S. Marine Air Ground Task Force known as Marine
Rotational Force-Darwin (at Royal Australian Air Force Base Darwin and Robertson Barracks)
and rotational deployments of U.S. Air Force bombers and fighters under the Enhanced Air
Cooperation (EAC) initiative.57 Additionally, as part of the Australia-United Kingdom-U.S.
(AUKUS) pact, U.S. and U.K. nuclear-powered submarines will begin rotational deployments to
Australia’s HMAS Stirling naval base in 2027 (U.S. submarines will also reportedly increase the
frequency of visits to this base beginning in 2023). 58 DOD’s increasing presence in Australia is
widely seen as a response to worsening relations between U.S.-aligned countries and the PRC.59
British Indian Ocean Territory (Diego Garcia)
The British Indian Ocean Territory (commonly referred to as Diego Garcia; a British Overseas
Territory) hosts Naval Support Facility Diego Garcia, a U.S. Navy-operated installation that
primarily provides logistical support for U.S. and allied forces operating in and around the
Persian Gulf and Indian Ocean. The site that would become Naval Support Facility Diego Garcia
was established by a secret bilateral agreement reached between the U.S. and British governments
in 1966; it has been the subject of some controversy owing to the claims of indigenous Chagos
Islanders forcibly displaced during the base’s construction.60
Other Indo-Pacific Sites
In addition to the locations described above, DOD has used a number of other sites west of the
International Date Line to base and support military forces. For example, Thailand’s location and
relations with the United States have led U.S. forces to use a number of Thai defense sites on a
rotational basis (e.g., U-Tapao Royal Thai Navy Air Field).61 U.S. Navy vessels also routinely

55 “U.S. Security Cooperation With Singapore,” U.S. Department of State, March 28, 2023, at https://www.state.gov/u-
s-security-cooperation-with-singapore/.
56 For more information and sources, see Appendix A – Key Sites and Facilities, “Singapore.”
57 See “United States Force Posture Initiatives,” Australian Department of Defence, at
https://www.defence.gov.au/programs-initiatives/united-states-force-posture-initiatives.
58 David Weber, “AUKUS deal: Jim Chalmers announces $8 billion HMAS Stirling naval base expansion,” Australian
Broadcasting Corporation, March 14, 2023 https://www.abc.net.au/news/2023-03-14/aukus-deal-jim-chalmers-hmas-
stirling-expansion-perth-wa/102092058 .
59 For more information and sources, see Appendix A – Key Sites and Facilities, “Australia.”
60 See “Exchange of Notes Constituting an Agreement concerning the Availability for Defence Purposes of the British
Indian Ocean Territory,” December 30, 1966, available online at https://treaties.un.org/doc/Publication/UNTS/
Volume%20866/volume-866-I-8737-English.pdf . For a recent summary of Chagossian claims against the U.S. and UK
governments, see “That’s When the Nightmare Started: UK and US Forced Displacement of the Chagossians and
Ongoing Colonial Crimes,” Human Rights Watch, February 15, 2023, at https://www.hrw.org/report/2023/02/15/thats-
when-nightmare-started/uk-and-us-forced-displacement-chagossians-and. For more information and sources, see
Appendix A – Key Sites and Facilities, “British Indian Ocean Territory.”
61 See Jim Garamone, “U.S., Thai Defense Leaders Look to Future in Indo-Pacific,” Department of Defense, May 13,
2022, at https://www.defense.gov/News/News-Stories/Article/Article/3030852/us-thai-defense-leaders-look-to-future-
in-indo-pacific/.
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conduct visits at a wide array of Indo-Pacific regional ports.62 Some analysts have also speculated
that, in the event of PRC military action against Taiwan, the United States may base significant
forces in Taiwan.63
Issues for Congress
Indo-Pacific Basing Posture
Congress may consider the degree to which the current U.S. basing posture—that is, the
geographical and functional distribution of bases in the Indo-Pacific region—supports strategic
priorities and operational requirements, under both peacetime and wartime conditions. Despite
considerable geopolitical, technological, and doctrinal change in recent years, much of DOD’s
basing posture remains, at least in part, the product of decisions made decades previously.
According to some observers, this has led to a misalignment between regional defense
infrastructure and the demands of the current and future threat environment. As one analyst
framed the problem in a 2022 editorial:
After more than a decade of promising to improve the survivability of U.S. forces in the
Indo-Pacific, the department has little to show for it. In part, ongoing wars in the Middle
East have inhibited efforts to rebalance the American military footprint to the Pacific, as
has the need to obtain the consent of nations that host American forces. Additionally, the
services prefer to fund their priority weapons, and their reticence to spend money on
supporting infrastructure is compounded when uncertainty about future base access is
factored in. Finally, the Defense Department has yet to break with its past approach to
power projection and to fully flesh out new operational concepts and ways of fighting.64
The basing posture issues for Congress may be divided into three distinct but related questions:
1. Where should U.S. bases be maintained or established?
2. To what extent should DOD distribute—or consolidate—regional basing
functions?
3. How resilient do U.S. bases need to be, and how can DOD improve infrastructure
resilience (to the extent it falls short of congressional goals)?
Placement
A fundamental question with respect to basing posture is that of placement—to achieve national
strategic aims and meet attendant operational requirements, where in the Indo-Pacific should the
United States operate military bases? In addressing this question, Congress may weigh the
tradeoffs between the advantages that proximity to likely operational areas could create for U.S.

62 See “CNO: Port visits expanding across Asia-Pacific,” Navy Times, September 24, 2014, at
https://www.navytimes.com/news/your-navy/2014/09/24/cno-port-visits-expanding-across-asia-pacific/.
63 As of this writing, DOD is reportedly planning to increase the number of U.S. military personnel in Taiwan from
approximately 30 to 100-200. Nancy Youssef and Gordon Lubold, “U.S. to Expand Troop Presence in Taiwan for
Training Against China Threat,” Wall Street Journal, February 23, 2023 at https://www.wsj.com/articles/u-s-to-
expand-troop-presence-in-taiwan-for-training-against-china-threat-62198a83. For advocacy of U.S. defense sites in
Taiwan, see Dominick Shortall and Jesse Johns, “Once unimaginable, some now debating return of U.S. forces to
Taiwan,” Japan Times, October 28, 2020, at https://www.japantimes.co.jp/news/2020/10/28/asia-pacific/us-forces-
taiwan-china/.
64 Stacie Pettyjohn, “Spiking the Problem: Developing a Resilient Posture in the Indo-Pacific,” War on the Rocks,
January 2022, at https://warontherocks.com/2022/01/spiking-the-problem-developing-a-resilient-posture-in-the-indo-
pacific-with-passive-defenses/.
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combat forces (especially air and naval), on the one hand, and the vulnerability such proximity
could produce for U.S. forces and infrastructure, on the other. Congress may also consider factors
such as the political and military reliability of countries hosting U.S. bases, as well as the
potential for significant posture changes to affect regional stability.
Although the President, as Commander-in-Chief, is ultimately responsible for the establishment
and disestablishment of military bases, Congress may legislate requirements, restrictions, and
other guidance (for instance, Congress has played a major role in shaping the Base Realignment
and Closure, or BRAC, process).65 Historically, this has tended to occur as part of the annual
defense authorization and appropriations processes.
As described above, locating military bases close to likely operational areas reduces the transit
time and resources required for U.S. forces to conduct combat operations in those areas. This is
especially significant for fighter and bomber aircraft, as their combat radii (the effective distance
an aircraft can fly, fight, and return) are constrained by the amount of fuel they can carry.66 Thus,
sites such as Okinawa’s Kadena Air Base (located approximately 400 miles from Taiwan, well
within the combat radius of relevant U.S. fighter and bomber aircraft) may be attractive to
military planners as convenient bases for air operations. However, the geography of the Indo-
Pacific is such that proximity to the areas of a prospective contingency—Taiwan being the most
prominent, but also areas of the South China Sea, the Korean peninsula, and parts of the Indian
Ocean—entails proximity to adversary air and missile strike capabilities. As Figure 5 below
illustrates, South Korea, most of Japan, and the northern portions of the Philippines may be
within range of PRC and DPRK short or medium-range ballistic missiles, while Guam and parts
of Japan, the Philippines, and Australia may be within range of PRC intermediate-range ballistic
missiles.

65 See CRS Report R45705, Base Closure and Realignment (BRAC): Background and Issues for Congress and CRS
Report R43102, “Fast Track” Legislative Procedures Governing Congressional Consideration of a Defense Base
Closure and Realignment (BRAC) Commission Report, by Christopher M. Davis for more information.
66 Combat radii differ by aircraft and mission type. For example, according to DVIDS, the F-35A has a combat radius
of 590 nautical miles, while an Air Force fact sheet reports that “in an air-to-surface role, the F-16 [radius is] more than
500 miles.” See “F-35A Combat Radius Lightning Flash Fact,” Defense Visual Information Distribution Service, May
10, 2022, at https://www.dvidshub.net/video/846194/f-35a-combat-radius-lightning-flash-fact# and “F-16 Fighting
Falcon,” U.S. Air Force at https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104505/f-16-fighting-falcon/
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Figure 5. Regional Missile Threat
Notional ranges of PRC ballistic missiles and U.S. regional defense sites

Source: CRS graphic based on PRC missile data and analysis from “Missiles of China,” Center for Strategic and
International Studies Missile Threat Project, April 12, 2021, at https://missilethreat.csis.org/country/china and
CRS analysis of DOD basing data.
Notes: Ranges are notional.
Some of the consequences of regional infrastructure placement for U.S. military performance are
explicitly examined in two studies of a hypothetical U.S.-China war. In an August 2022 report
(“Can China Take Taiwan? Why No One Really Knows”), Brookings Institute analyst Michael
O’Hanlon evaluated whether the PRC could successfully conquer Taiwan. Using open-source
data and estimates on Chinese and U.S. orders of battle, weapons capabilities and inventories, and
doctrine, O’Hanlon modelled two scenarios for a U.S.-China conflict over Taiwan: “a maritime
fight centered on submarines” (Scenario 1); and “a broader subregional war” (Scenario 2). In both
scenarios, regional U.S. bases play a role. In Scenario 1, O’Hanlon speculates that air bases in
Japan may be used to host anti-submarine (ASW) and fighter aircraft for use against Chinese
maritime and air platforms enforcing a blockade of Taiwan, while in Scenario 2, O’Hanlon
models the use of U.S. and allied bases in Japan and Guam to launch air and naval operations
against Chinese maritime, air, and ground platforms, personnel, and infrastructure in and around
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Taiwan and mainland China.67 Given their role in enabling U.S. combat operations, these bases
would likely come under Chinese attack—especially in a situation resembling O’Hanlon’s
Scenario 2, which sees aircraft and land-based missiles striking U.S. installations in mainland
Japan, Okinawa, and Guam, with a high probability of destroying or damaging most
infrastructure targets.68
In a January 2023 report, three analysts at the Center for Strategic and International Studies
(CSIS) summarized the results and implications of a wargame simulating the initial phases of a
U.S.-China war precipitated by an invasion of Taiwan.69 Using open-source data and estimates,
CSIS developed and ran 24 iterations of a wargame under “base case,” “pessimistic,” and
“optimistic” parameters. As in the Brookings study described above, the U.S. sought to support
air and naval operations in and around Taiwan and mainland China from bases in Japan and
Guam, and the PRC sought to deny the use of those bases through kinetic attacks. In most of the
“pessimistic” and “base case” iterations, U.S. air bases in mainland Japan, Okinawa, and Guam
were subjected to effective Chinese missile attacks, damaging infrastructure and causing the
majority of U.S. combat aircraft losses.70
The debate over basing fighter aircraft at Kadena Air Base (AB) on Okinawa provides another
illustration of this dynamic. In October 2022, the Air Force announced that it would begin a
phased withdrawal of two F-15C and D fighter squadrons formerly based at Kadena AB.71 The
withdrawal, to be accomplished in phases over a two-year period, faced criticisms from some
analysts concerned the move might undermine regional deterrence (several Members of Congress
delivered a letter to the Secretary of Defense alleging the move would create a “tangible
reduction in American forward combat power”).72 However, others have defended the move,
arguing that Chinese strike capabilities make Kadena “uniquely ill-positioned for permanently
basing large numbers of American aircraft” and instead advocating for a more geographically
dispersed and rotational approach to regional basing.73
Congress may assess the tradeoffs between the proximity of defense sites to likely operational
areas and the resultant vulnerability to adversary attack. This assessment could in turn inform
congressional direction to DOD regarding the implementation of basing posture, as well as
congressional prioritization of defense outlays.
In considering the question of base placement, Congress may also note that DOD’s regional
basing posture—along with its broader force posture—has remained broadly consistent over the

67 Michael O’Hanlon, “Can China Take Taiwan? Why No One Really Knows,” Brookings Institute, August 2022, pp.
24-26, at https://www.brookings.edu/research/can-china-take-taiwan-why-no-one-really-knows/?amp.
68 O’Hanlon also argues that the escalation of a crisis from the limited maritime conflict envisioned in Scenario 1 to the
expanded war envisioned in Scenario 2 might come about as a result of PRC attacks on U.S. bases: “If [China’s]
leaders saw the United States using air bases in places like Okinawa to fly sorties (for example, with P-3 and P-8
aircraft) that were killing Chinese submariners and to establish air dominance (for example, with F-22 fighters)…there
would be powerful incentives to strike at the origins of those flights.” O’Hanlon, “Can China Take Taiwan,” p. 20.
69 Mark Cancian, Matthew Cancian, and Eric Heginbotham, The First Battle of the Next War (Washington, D.C.:
Center for Strategic and International Studies, 2023) available at https://csis.org/analysis/first-battle-next-war-
wargaming-chinese-invasion-taiwan.
70 Ibid. pp. 83-115.
71 Stephen Losey, “Air Force to replace Kadena F-15 squadrons,” Defense News, October 27, 2022, at
https://www.defensenews.com/air/2022/10/27/air-force-to-replace-kadena-f-15-squadrons-with-rotational-fighters.
72 Letter available at https://www.rubio.senate.gov/public/_cache/files/afe5d67d-0f67-42e3-ac04-a2a23ecbb685/
D9D9779A4044CC4A162EC74FD42454A9. 11.01.22--rubio-et-al-letter-to-secdef-re-okinawa-f-15s.pdf
73 Stacie Pettyjohn, Andrew Metrick, and Becca Wasser. “The Kadena Conundrum,” War on the Rocks, December 1,
2022, at https://www.warontherocks.com/2022/12/the-kadena-conundrum-developing-a-resilient-indo-pacific-posture.
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past three decades.74 As the Brookings Institute’s Andrew Yeo and Michael O’Hanlon observe in
a February 2023 report:
Broadly speaking, the U.S. force posture in the Pacific looks very much like it did in the
mid-1990s, with the preponderance of America’s 100,000-strong troop presence there
concentrated in Japan and South Korea. Since that time, the only major changes involving
thousands of forces have been the reduction in the U.S. Army presence in South Korea by
about 10,000 in the early 2000s and the more recent gradual shift of about half of the 18,000
U.S. Marines on Okinawa to Guam.75
Although the number and distribution of DOD-operated installations has remained broadly
consistent since the mid-1990s, one way that the United States has sought to expand its regional
infrastructure footprint has been through the negotiation of access to bases operated by allied or
partner governments (an approach sometimes termed ‘places not bases’).76 Since 2011, DOD has
increased regional deployments to Australian sites (particularly in the Northern Territory and
Queensland) and, under the U.S.-Philippines Enhanced Defense Cooperation Agreement
(EDCA), secured access on a rotational basis to nine Philippine military bases (mainly on the
northern islands of Luzon and Palawan).77 Despite this expansion, some observers have identified
areas of the Indo-Pacific where U.S. presence and access could be increased. Yeo and O’Hanlon
write that “a particularly large hole in U.S. force posture exists in Southeast and South Asia where
basing access agreements remain limited,” and identify the pursuit of basing rights in the area as a
potential option for policymakers.78
A related issue for congressional consideration is the degree to which the United States may rely
upon countries hosting U.S. military bases to allow access in the event of a contingency. For
example, the importance of Philippine bases to U.S. plans for a potential conflict has grown
considerably over the past decade—so much so that, as former PACOM commander Admiral
(Ret.) Harry Harris stated in 2023 before the House Armed Services Committee, “it's hard to
imagine a fight with the PRC without being able to use bases on the Philippines.”79 Statements by
Philippine officials in 2022 and 2023—including President Ferdinand Marcos, Jr.—suggest that
permission for U.S. forces to operate from these bases would be granted only under certain
circumstances, and that DOD will not be permitted to undertake “offensive action” from EDCA
sites.80

74 Although neither “force posture” nor “basing posture” are statutorily or doctrinally defined, “force posture” is used in
this report to denote the distribution and disposition of all elements of military power, while “basing posture” is used to
denote the distribution and disposition of fixed facilities owned, operated, or used by DOD for military purposes.
75 Andrew Yeo and Michael E. O’Hanlon, “Geostrategic Competition and Overseas Basing in East Asia and the First
Island Chain,” Brookings Institute, February 2023, p. 2, at https://www.brookings.edu/research/geostrategic-
competition-and-overseas-basing-in-east-asia-and-the-first-island-chain/
76 See Colonel Michael W. Pietrucha, “Making Places, Not Bases a Reality,” U.S. Naval Institute Proceedings, Vol.
141, October 2015, at https://www.usni.org/magazines/proceedings/2015/october/making-places-not-bases-reality .
77 See David Vergun, “New EDCA Sites Named in the Philippines,” Department of Defense, April 3, 2023, at
https://www.defense.gov/News/News-stories/article/article/3350297/new-edca-sites-named-in-the-philippines/.
78 Yeo and O’Hanlon also outline the drawbacks such expansion might entail, discussed later in this subsection.
“Geostrategic Competition and Overseas Basing in East Asia,” p. 3.
79 “House Armed Services Committee Holds Hearing on Chinese Threats to U.S. National Defense,” February 7, 2023.
Available online at https://armedservices.house.gov/hearings/full-committee-hearing-pressing-threat-chinese-
communist-party-us-national-defense.
80 See Kristina Maralit, “Marcos rules out offensive actions from new EDCA sites,” The Manila Times, April 11, 2023.
It should also be noted that the Philippine ambassador to the U.S. said in September 2022 that the Philippines would
allow U.S. forces to operate from EDCA bases “only if it is important for us, for our own security,” Ryo Nakamura and
Yuichi Shiga, “Philippines may allow U.S. military access during Taiwan crisis,” Nikkei Asia, September 5, 2022 at
https://asia.nikkei.com/Editor-s-Picks/Interview/Philippines-may-allow-U.S.-military-access-during-Taiwan-crisis.
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Although this concern may be especially pronounced for countries that now host U.S. forces at
non-DOD-operated facilities (such as the Philippines and Singapore), some commentators have
also posited that even countries that have hosted DOD-operated facilities for decades, such as
South Korea or Japan, may impose limits on U.S. usage of bases to avoid provoking Chinese
attacks.81 Congress may consider the appropriate balance of risk, as well as direct planning for
alternate basing options in the event of such a situation. Congress may also consider the
appropriate level of infrastructure investment in sites to which future DOD access may be
uncertain.82
Finally, Congress may consider how changes in basing posture affect broader geopolitical
developments in the Indo-Pacific. Among international relations scholars, the concept of the
security dilemma—a problem in which states, by taking measures to improve their own security,
may threaten others—occupies a central role. Some commentators have argued that this dynamic
exists in the contemporary Indo-Pacific, and that U.S. basing is a factor:
The same dynamic [i.e., the security dilemma] is operating in Asia. Not surprisingly, China
regards America’s long position of regional influence—and especially its network of
military bases and its naval and air presence—as a potential threat. As it has grown
wealthier, Beijing has quite understandably used some of that wealth to build military
forces that can challenge the U.S. position… Each side’s efforts to deal with what it regards
as a potential security problem merely reinforced the other side’s own security fears,
thereby triggering a response that strengthened the former’s original concerns. Each side
sees what it is doing as purely defensive reaction to the other side’s behavior, and
identifying “who started it” soon becomes effectively impossible.83
PRC officials have strongly criticized recent U.S. moves to expand its regional defense
infrastructure footprint, alleging that measures such as the addition of new sites to the U.S.-
Philippines EDCA “are part of U.S. efforts to encircle and contain China” and will “endanger
regional peace and stability.”84 On the other hand, some policymakers and analysts have argued
that establishing additional bases could strengthen U.S. deterrence of PRC aggression and thereby

81 See, for instance, Denny Roy, “South Korea will stay out of a Taiwan Strait War,” The Diplomat, March 21, 2023, at
https://thediplomat.com/2023/03/south-korea-will-stay-out-of-a-taiwan-strait-war/; and Gabriel Dominguez, “Crucial
Role: Defense of Taiwan hinges on Japan’s support,” Japan Times, January 23, 2023, at https://www.japantimes.co.jp/
news/2023/01/23/national/japan-role-us-taiwan-conflict/.
82 Per testimony given by INDOPACOM Commander Admiral Aquilino in an April 2023 hearing before the House
Armed Services Committee, “There are identified projects [in the Philippines] that that we would like to build out in
the current sites, that they've agreed with that, we have started work on.” “House Armed Services Committee Holds
Hearing on Indo-Pacific National Security Challenges,” April 18, 2023, transcript available via CQ at
https://plus.cq.com/doc/congressionaltranscripts-7718539?5.
83 Stephen M. Walt, “Does Anyone Still Understand the ‘Security Dilemma’?” Foreign Policy, July 26, 2022 at
https://foreignpolicy.com/2022/07/26/misperception-security-dilemma-ir-theory-russia-ukraine/.
84 “Statement of the Spokesperson of the Chinese Embassy in the Philippines,” Embassy of the PRC in the Republic of
the Philippines, March 12, 2023, at http://ph.china-embassy.gov.cn/eng/sgdt/202303/t20230312_11039384.htm.
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decrease the likelihood of a crisis.85 In weighing whether to establish additional bases, Congress
may consider potential effects on Indo-Pacific stability.86
Organization
Aside from the question of where to maintain or seek basing more generally, Congress may also
consider issues relating to base organization and operation. Historically, DOD has created larger,
consolidated installations in the Indo-Pacific, clustering many defense functions within mainly
DOD-operated sites. However, as described above, the Army, Air Force, Navy, and Marine Corps
have each begun to develop and implement new concepts for more distributed combat and
logistical operations. These operational concepts propose a different use of infrastructure, one in
which larger, permanent, and concentrated bases are supplemented by—and, in some cases,
replaced or used interchangeably with—smaller, temporary, non-U.S.-operated, or distributed
facilities.87
As an example of how these shifts may affect regional basing posture, CSIS senior fellow Bonny
Lin offered the following characterization of Indo-Pacific infrastructure in a February 2023
Senate Armed Services Committee hearing:
Our infrastructure in the Indo-Pacific, particularly the fact that we are now investing in
more resilient and dispersed basing is absolutely critical, particularly as we look at the
range of [PRC] missiles…The range of missiles that China can bring to bear means that in
any fight over Taiwan, we will need to be able to disperse our assets so we're not reliant on
any particular base. And in order to be able to maintain that… we need to harden our
infrastructure. We also need to work with our allies and partners to make sure that we have
the capabilities to quickly repair, for example, runways and other facilities.88
To some extent, this conceptual perspective is manifested in DOD doctrine for —and investments
in—regional infrastructure. For example, in a March 2023 interview, the commander of Pacific
Air Forces (PACAF) stated that “from the Agile Combat Employment standpoint, what we're
spending our dollars on this year is expanding the number of places that we can go to, and of the
places that we're already at [sic], expanding the capability at those places.”89
However, some analysts have identified potential drawbacks to a more distributed basing posture.
A January 2023 report by the RAND Corporation found that operating from more dispersed air
bases could pose significant sustainment and communication challenges, and cautioned that such

85See, for instance, CNAS analyst Stacie Pettyjohn’s argument that the U.S. should “gain access to more bases” in
“Spiking the Problem: Developing a Resilient Posture in the Indo-Pacific,” War on the Rocks, January 10, 2022
(available at https://warontherocks.com/2022/01/spiking-the-problem-developing-a-resilient-posture-in-the-indo-
pacific-with-passive-defenses/ and Senator Roger Wicker’s statement that DOD “cannot successfully deter Xi with a
brittle basing and logistics infrastructure,” in “Senate Armed Services Committee Holds Hearing on Fiscal Year 2024
Budget Request for the Department of Defense”, March 28, 2023, available at https://plus.cq.com/doc/congressional
transcripts-7700800?7.
86 In addition to effects stemming from PRC responses, Congress may wish to consider effects that may be produced by
Russian and DPRK responses to significant shifts in U.S. regional basing posture.
• 87 See discussion under the “
Strategic and Operational Role” heading on page 11 of this report.
88 Senate Armed Services Committee Hearing on Global Security Challenges and Strategy, February 15, 2023.
Transcript available at https://plus.cq.com/doc/congressionaltranscripts-7667132?18
89 General Kenneth Wilsbach, quoted in Sean Carberry, “Forget Hardened Bases, Pacific Conflict Requires Agile
Combat Employment, Commander Says,” National Defense, March 8, 2023 at
https://www.nationaldefensemagazine.org/articles/2023/3/8/forget-hardened-bases-pacific-conflict-requires-agile-
combat-employment-commander .
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bases “may not be more survivable than those closer to the threat if the farther bases can be
brought down by a small number of missiles” due to their smaller size or a lack of protective
systems and infrastructure.90
Congress may consider the costs and benefits of a more distributed approach to regional basing
functions, assess the extent to which DOD is implementing such an approach, and deliberate on
the desirability of additional investments to modify the concentration or distribution of base
facilities.
Resilience
Another aspect of posture Congress may consider is the resilience—broadly defined as the ability
to resist, adapt to, and recover from disruption—of Indo-Pacific installations.91 Given the regional
environment described above, DOD has tended to structure its resilience efforts around the threat
of kinetic attack, particularly by PRC air and missile capabilities.
When it comes to protecting bases from air and missile attacks, analysts typically distinguish
between active and passive defenses. Active defenses are measures that seek to neutralize
incoming threats before they are able to strike their targets—whether by kinetic interception, as
with the THAAD or PATRIOT missile defense systems, or through the use of newer technologies
like directed energy and microwave-based countermeasures.92 Passive defenses are measures
intended to decrease the damage, disruption, and general impact of adversary attacks, and may
include the construction of protective physical structures (e.g., hardened aircraft shelters), the
development of repair and damage control capabilities, and practices such as the dispersal or
concealment of vulnerable assets.93
The appropriate balance between active and passive defenses has been the subject of debate
among policymakers and commentators. Some analysts, such as the Hudson Institute’s Rebeccah
Heinrichs, emphasize the centrality of active defenses:
While passive defenses including tactics intended to deceive an adversary and fortification
of military infrastructure to sustain an attack are important, there is no substitute for a
layered active defense. To achieve cost-effectiveness, some budget offices may be tempted
to over-rely on passive defenses, but that would be a grave mistake. The US military must
have the ability to blunt the impact of a fast PRC attack, and that means preventing missiles
from hitting key targets.94

90 Christopher Lynch, Rachel Costello, Jacob L. Heim, et al. “Operational Imperative: Investing Wisely to Bolster U.S.
Air Bases Against Chinese and Russian Attacks.” RAND Corporation, January 2023, p. 4.
91 A more specific definition of resilience is offered by the RAND Corporation: “the capacity of a force to withstand
attack, adapt, and generate sufficient combat power to achieve campaign objectives in the face of continued, adaptive
enemy action.” Hagen, Jeff, Forrest E. Morgan, Jacob L. Heim, and Matthew Carroll, “The Foundations of Operational
Resilience—Assessing the Ability to Operate in an Anti-Access/Area Denial Environment,” available at
https://www.rand.org/pubs/research_reports/RR1265.html
92 For more on directed energy technologies, see CRS In Focus IF11882, Defense Primer: Directed-Energy Weapons,
by Kelley M. Sayler.
93 The DOD Dictionary of Military and Associated Terms defines active defense as “the employment of limited
offensive action and counterattacks to deny a contested area or position to the enemy” and passive defense as
“measures taken to reduce the probability of and to minimize the effects of damage caused by hostile action without the
intention of taking the initiative.” DOD Dictionary of Military and Associated Terms, Department of Defense, February
2023, pp. 7 and 151.
94 Rebeccah Heinrichs, “Introduction,” in Rebecca Heinrichs (editor), Defending Guam (Washington, D.C.: Hudson
Institute, 2022), p. 9. Available at https://s3.amazonaws.com/media. hudson.org/Defending+Guam+July+2022.pdf
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Other analysts maintain that active defenses, while useful, can be expensive and vulnerable to
attack. A January 2023 study by the RAND Corporation argues that:
the most-cost-effective ways to improve air base resilience are robust, passive
defenses…[including] hardened shelters for aircraft; dispersal of aircraft; redundant fuel
supplies; prepositioned munitions; rapid runway repair capabilities; and tailored forms of
camouflage, concealment, and deception.95
The publicly available studies and wargames that examine a potential conflict with a strategic
competitor suggest that the resilience of Indo-Pacific installations—particularly air bases—may
be a factor in such a conflict’s outcome.96
Congress may assess the desirability and efficacy of additional investments in resilience-building
measures at Indo-Pacific bases, and weigh the respective benefits of active and passive defenses.
Resourcing Regional Defense Infrastructure
Congress funds the establishment and sustainment of defense infrastructure through the Military
Construction and Operation and Maintenance appropriations titles. In addition, beginning in
FY2021, Congress has authorized a particular set of Indo-Pacific defense infrastructure
appropriations as part of the Pacific Deterrence Initiative (PDI), a group of regionally-focused
defense investments and activities typically included as part of the annual National Defense
Authorization Act (NDAA).
Military Construction
Military construction (MILCON) appropriations fund construction, development, conversion, or
extension activities carried out with respect to a military installation, as well as any DOD
acquisitions of real property (for more information on MILCON authorities and activities, see
CRS Report R44710, Military Construction: Authorities and Processes).
Over the past four fiscal years, annual military construction appropriations for Indo-Pacific sites
have ranged from a low of $1.37 billion to a high of $3.54 billion (see Table 1 below).

95 Christopher Lynch, Rachel Costello, Jacob L. Heim, et al. “Operational Imperative: Investing Wisely to Bolster U.S.
Air Bases Against Chinese and Russian Attacks.” RAND Corporation, January 2023, p. 4.
96For two examples, see O’Hanlon, Can China Take Taiwan and Cancian et al., The First Battle of the Next War.
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Table 1. Military Construction Appropriations, FY2020-23
($ in thousands)
Appropriations for Indo-Pacific
Appropriations for
Appropriations for military
military construction as a
military construction,
construction, Indo-Pacific
percentage of global military
FY
worldwidea
regionb
construction
2020
$8,228,813c
$1,812,956
22.0%
2021
$5,599,209
$1,368,810
24.4%
2022
$9,033,782
$2,267,292
25.1%
2023
$12,194,728
$3,542,995
29.1%
Total
$35,056,532
$8,992,053

Source: CRS Analysis of Military Construction, Veterans Affairs, and Related Agencies Appropriations Acts,
2020-2023 and accompanying Joint Explanatory Statements.
Notes:
a. Figures for “Appropriations for Military Construction, Worldwide” include all appropriations for Army,
Navy and Marine Corps, Air Force, Defense-wide, Army National Guard, Air National Guard, Army
Reserve, Navy Reserve, and Air Force Reserve Military Construction. They do not include NATO Security
Investment, DOD Base Closure Account, Family Housing Construction, Family Housing O&M, Family
Housing Improvement Fund, or Military Unaccompanied Housing Improvement Fund monies.
b. Figures for “Indo-Pacific MILCON appropriations” include appropriations for projects in: Alaska;
Washington; California; Hawaii; Guam and the Marianas; the Republic of the Marshall Islands, Palau, and
Micronesia; Japan; South Korea; the Philippines; Singapore; Diego Garcia; and Australia.
c. The FY2020 MILCON appropriation also included $10 mil ion for “Defense-Wide planning and design for
emergent requirements in INDOPACOM” (See Congressional Record, Vol. 165, No. 204-Book III, p.
H11378).
As Table 1 illustrates, the proportion of MILCON appropriations funding projects at Indo-Pacific
sites has every fiscal year since FY2020. In FY2023, selected Indo-Pacific bases with projects
receiving MILCON appropriations included:97
• Fort Wainwright, Alaska ($99 million for a physical fitness center annex);
• Joint Base Elmendorf-Richardson ($63 million for an aircraft maintenance
hangar)
• Clear Space Force Station, Alaska ($68 million for a new dormitory);
• Joint Base Elmendorf-Richardson, Alaska ($100 million to extend runway
16/34);
• Naval Air Station Whidbey Island, Washington ($68.1 million for airfield
pavement improvements);
• Camp Pendleton, California ($85.2 million for Basilone Road Realignment);
• Twentynine Palms ($120.4 million for a range simulation training and
operations facility);

97 This list is not comprehensive; rather, it represents an attempt to identify high-value regional projects with significant
regional warfighting and readiness relevance. For a complete list of projects receiving FY2023 MILCON
appropriations, see “Joint Explanatory Statement for Consolidated Appropriations Act, 2023 – Division J, Military
Construction, Veterans Affairs, and Related Agencies,” Senate Appropriations Committee, pp. 94-114, available at
https://www.appropriations.senate.gov/imo/media/doc/Division%20J%20-%20Mil%20Con%20Statement%20
FY23.pdf.
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• Naval Air Station Lemoore, California ($201.3 million for F-35C maintenance
hangar and airfield pavement);
• Vandenberg Space Force Base, California ($89 million for consolidated
maintenance facility);
• Naval Base Coronado, California ($75.7 million for a SOF operations support
facility);
• Schofield Barracks, Hawaii ($111 million for the construction of company
operations facilities);
• Joint Base Pearl Harbor-Hickam, Hawaii ($621.2 million for the replacement
of Dry Dock 3 and $103.4 million for the construction of missile magazines);
• Marine Corps Base Hawaii, Hawaii ($87.9 million for bachelor enlisted
quarters);
• Naval Base Guam, Guam ($131.6 million for 9th Engineer Support Battalion
equipment and maintenance facility and $149.3 million ground combat element
infantry battalion 1 and 2 facilities);
• Tinian, Northern Mariana Islands ($58 million for airfield development and
$92 million for fuel tanks);
• Army Garrison-Kwajalein Atoll, Marshall Islands ($69 million for a medical
clinic);
• Kadena Air Base, Japan ($94.1 million for Marine Corps bachelor enlisted
quarters, $101.3 million for a Marine Corps barracks complex, $71 million for a
helicopter operations maintenance hangar, and $77 million for a theater a/c
corrosion control center);
• Marine Corps Air Station Iwakuni, Japan ($85 million for bulk fuel storage
tanks);
• Yokota Air Base, Japan ($72.2 million for operations and warehouse facilities);
• Royal Australian Air Force Base Darwin, Australia ($72.4 million for aircraft
parking apron).
Although Indo-Pacific military construction appropriations have increased in both absolute and
proportional terms since FY2020, some analysts and Members of Congress argue that regional
MILCON activities have been insufficient to meet U.S. requirements. In the joint explanatory
statement accompanying the FY2023 Military Construction, Veterans Affairs, and Related
Agencies Appropriations Act, the Committees expressed concern that “the Services have not
properly prioritized projects within INDOPACOM in recent fiscal years, instead choosing to fund
projects that are specifically beneficial to the Service and not necessarily the joint mission.”98
Some commentators attribute what they consider insufficient MILCON funding to structural
factors. In a 2022 piece for War on the Rocks, for example, three analysts at the Center for a New
American Security argued that Indo-Pacific infrastructure upgrades “have been habitually
shortchanged because the services prefer to invest in force structure and Congress does not like
spending money overseas.”99

98 “Division J – Military Construction, Veterans Affairs, and Related Agencies Appropriations Act, 2023,” p. 4,
available at https://www.appropriations.senate.gov/imo/media/doc/Division%20J%20-%20Mil%20Con%20
Statement%20FY23.pdf
99 Pettyjohn, “The Kadena Conundrum.”
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Congress may consider assessing whether the level of funding for Indo-Pacific military
construction projects provided in recent appropriations acts is adequate (in both absolute terms
and as a proportion of overall MILCON spending) to meet current and future military
requirements, particularly if significant changes to basing posture are anticipated.
Facilities Sustainment, Restoration, and Modernization
A number of analysts, DOD officials, and Members of Congress have expressed concern about
the condition of Indo-Pacific defense infrastructure. In a February 2023 Senate Armed Services
Committee hearing, for example, Senator Mazie Hirono (HI) offered the following
characterization of the challenges facing DOD infrastructure:
“Clearly, there are many demands on our resources—that is an understatement—and I
would consider a foundational concern to be the need to invest in our infrastructure, which
is not only a matter of geopolitical competition, but also the readiness of the forces… In
the last year, there have been numerous issues with the military’s infrastructure in
Hawaii—from water main breaks to toxic chemical leaks and spills endangering our
groundwater. And I know that these kinds of events are not particular to Hawaii. Across
the country, we need to better maintain and modernize our DOD infrastructure to take care
of our people, get our systems out of maintenance on time, and be able to support national
security.”100
Although the Indo-Pacific region has experienced several high-visibility infrastructure problems
(e.g., the Red Hill Bulk Fuel Storage Facility leak), the issue of poor infrastructure condition is
not unique to the region.101 In a 2022 report, the Government Accountability Office found that
DOD had a deferred maintenance backlog that would require at least $130 billion to eliminate,
creating “significant risk to [the Department’s] objective of maintaining facilities in good working
order to meet working requirements.”
Facilities sustainment, restoration, and modernization (FSRM) activities on military installations
are funded by Operation and Maintenance (O&M) appropriations. Unlike MILCON spending,
FSRM funding information—as documented in DOD budget requests and congressional
authorization and appropriation legislation—is not typically disaggregated by specific locations
or installations, making it difficult to assess the level of funding by site or region.102 In FY2023,
Congress appropriated approximately $16.8 billion for FSRM activities across DOD, with the
Army (approximately $5.1 billion), Air Force (approximately $4.4 billion), and Navy
(approximately $4 billion) receiving the largest amounts, respectively.103
Given the strategic and operational importance of Indo-Pacific defense sites, Congress may assess
the extent to which more detailed budget reporting by DOD, adjustments to FSRM funding, or
further studies of related infrastructure issues may be necessary to meet military requirements.

100 “Senate Armed Services Committee Hearing on Global Security Challenges and Strategy”, February 15, 2023. Sen.
Hirono statement available at https://www.hirono.senate.gov/news/press-releases/video-hirono-highlights-importance-
of-infrastructure-updates-pacific-allies-to-us-national-security
101 For more information on Red Hill, see “Red Hill Bulk Fuel Storage Site in Hawai’I,” Environmental Protection
Agency, at https://www.epa.gov/red-hill .
102 For more information on this and military construction appropriations more generally, see CRS Report R44710,
Military Construction: Authorities and Processes.
103 CRS analysis of information provided in the Joint Explanatory Statement for the Department of Defense
Appropriations Act, 2023.
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Pacific Deterrence Initiative
In FY2021, Congress established the Pacific Deterrence Initiative (PDI), a set of prioritized
defense investments and activities intended to “enhance the United States deterrence and defense
posture in the Indo-Pacific region, assure allies and partners, and increase capability and
readiness in the Indo-Pacific region.”104 PDI is not a separate funding source; rather, its purpose is
to “focus resources on capability gaps” and “enhance budgetary transparency and oversight” by
identifying and collating Indo-Pacific-focused spending and programs from the broader DOD
budget.105
In FY2022 and FY2023, activities authorized under PDI were divided into five categories:
• Presence and Posture ($4.1 billion authorized in FY2022, $6.46 billion
authorized in FY2023)
• Logistics and Prepositioning of Equipment ($360 million authorized in FY2022,
$500 million authorized in FY2023)
• Exercises, Training, and Experimentation ($696 million authorized in FY2022,
$2 billion authorized in FY2023)
• Defense and Security Capabilities of Allies and Partners ($489 million authorized
in FY2022, $732 million authorized in FY2023)
• Infrastructure Improvements ($1.5 billion authorized in FY2022, $1.8 billion
authorized in FY2023)
The Infrastructure Improvements category includes authorizations for projects funded through
both military construction (MILCON) and operation and maintenance (O&M) appropriations.
Examples of authorized PDI projects under this category include:
• Bulk storage tanks at MCAS Iwakuni (FY2023, $85 million, MILCON);
• Aircraft parking apron at RAAF Base Darwin, Australia (FY2023, $72.4 million,
MILCON);
• Fuel tanks with pipeline and hydrant system on Tinian, Northern Mariana Islands
(FY2023, $92 million, MILCON);
• Japan vehicle maintenance shop (FY2023, $80 million, MILCON);
• Air Force infrastructure improvements (FY2022 and FY2023, $404.3 million and
$412.4 million, O&M);
• Marine Corps FSRM (FY2022 and FY2023, $112.1 million and $127.2 million,
O&M);
• Corrosion control hangar for C-130J at Yokota Air Base (FY2022 and FY2023,
$67 million and $10 million, MILCON);
• Joint Communication Upgrade at Naval Base Guam (FY2022, $84 million,
MILCON);
• Extended runway at JBE-R (FY2022, $79 million, MILCON).106

104 See Section 1251 of the William M. (Mac) Thornberry FY2021 National Defense Authorization Act (P.L. 116-283).
105 See S.Rept. 116-236, p. 3; for more information on PDI, see CRS In Focus IF12303, The Pacific Deterrence
Initiative: A Budgetary Overview.
106“ Joint Explanatory Statement accompanying James M. Inhofe National Defense Authorization Act for Fiscal Year
2023,” p. 302, available at https://rules.house.gov/sites/republicans. rules118. house.gov/files/BILLS-117HR7776EAS-
RCP117-70-JES.pdf#page=302.
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With respect to PDI generally, some analysts and Members of Congress have contended that
DOD implementation of PDI priorities has been misaligned with congressional intent.107 In the
National Defense Authorization Acts (NDAAs) for FY2022 (P.L. 117-81) and FY2023 (P.L. 117-
263), PDI authorizations differed significantly from DOD requests, with Congress redistributing
or adding billions of dollars in proposed PDI investments. The FY2023 House Appropriations
Committee report (H.Rept. 117-388) expressed "concern that DOD has failed to provide adequate
accounting for the funding requested" under PDI, and directed DOD to augment the budgetary
and programmatic descriptions of PDI activities in its FY2024 budget documentation.
With respect to infrastructure more specifically, there were also considerable discrepancies
between:
• the FY2023 spending DOD requested under the “Infrastructure Improvements”
category ($1.21 billion);
• the FY2023 spending INDOPACOM requested under the “Infrastructure,
Responsiveness, and Resilience” category as part of a congressionally mandated
report separate from DOD’s formal budget request ($726 million) and;108
• the FY2023 spending Congress authorized for PDI in the FY2023 NDAA ($1.8
billion)
Additionally, the criteria according to which DOD categorizes infrastructure activities in its
budget requests are unclear. Although there is an “Infrastructure Improvements” category, in its
FY2023 PDI budget documentation DOD requested funding for infrastructure-related activities
(i.e., MILCON and FSRM) under four of the six PDI categories.109 As an example, a combined
$129 million of MILCON funding was requested for bulk fuel storage tanks at Marine Corps Air
Station Iwakuni and Yokota Air Base under the “Improved Logistics, Maintenance, and
Prepositioning” category, while $39 million of MILCON funding was requested for missile
defense infrastructure under the “Modernized and Strengthened Presence” category.
Congress may consider whether modifications to PDI are desirable to: clarify the purpose and
intent of activity categories; increase the detail that DOD provides in its congressional
documentation; and ensure that infrastructure activities are aligned with strategic aims and
military requirements (especially those created by the implementation of new operational
concepts).

107 See, for example, Dustin Walker, “Show Me the Money: Boost the Pacific Deterrence Initiative,” War on the Rocks,
June 29, 2022, at https://warontherocks.com/2022/06/show-me-the-money-boost-the-pacific-deterrence-initiative/ and
the “Joint Explanatory Statement to Accompany the National Defense Authorization Act for Fiscal Year 2022,” pp.
280-281, available at https://rules.house.gov/sites/republicans.rules118.house.gov/files/17S1605-RCP117-21-JES-
U1.pdf .
108 INDOPACOM report available via Defense One at https://www.defenseone.com/policy/2022/05/report-seize-
initiative/366380/.
109 The categories under which DOD submitted its PDI request differed from those under which Congress authorized
funding in the enacted NDAA. DOD categories were: 1) Modernized and Strengthened Presence; 2) Improved
Logistics, Maintenance, and Prepositioning; 3) Exercises, Training, Experimentation, and Innovation; 4) Infrastructure
Improvements; 5) Building the Defense and Security Capabilities, Capacity and Cooperation of Allies and Partners;
and 6) Improved Capabilities Available to U.S. Indo-Pacific Command (joint and enabling headquarters capabilities.
Infrastructure spending was requested under the first four categories.
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Appendix A. Key Sites and Facilities
This appendix provides descriptions of key sites and facilities covered by this report, as well as a
consolidated list of major Indo-Pacific bases (see Table A-1 below).
Alaska
Fort Wainwright. Fort Wainwright is an Army installation located in Fairbanks, AK. It occupies
approximately 756,530 acres, and hosts the 1st Infantry Brigade, 11th Airborne Division (an
infantry brigade combat team) as well as the 1st Battalion, 25th Aviation Regiment (an AH-64
Apache attack reconnaissance battalion) and the 1st Battalion, 52nd Aviation Regiment (a general
support aviation battalion with UH-60 Blackhawks, CH-47 Chinooks, and UH-60 medevac
support).110
Fort Greely. Fort Greely is an Army installation located about 100 miles southeast of Fairbanks,
AK. It occupies approximately 7,200 acres, and supports midcourse missile defense.111 It hosts
the Ground-Based Midcourse Defense anti-ballistic missile interception system, the 49th Missile
Defense Battalion, 100th Missile Defense Brigade (which operates and secures the ground-based
midcourse defense system), the 59th Signal Battalion (which conducts strategic signal operations
for missile command), and the Cold Regions Test Center (which tests materiel and equipment in
cold weather conditions).112
Joint Base Elmendorf-Richardson (JBER). JBER is a joint Army-Air Force installation located
near Anchorage, AK. It occupies approximately 73,000 acres, and hosts the Army’s 2nd Infantry
Brigade, 11th Airborne Division, (an airborne brigade combat team), as well as the Air Force’s 11th
Air Force and 3rd Wing, which consists of two F-22 fighter squadrons, one E-3 command and
control squadron, and one mixed C-17/C-12 airlift squadron. In addition, JBER is also home to
the Alaska Air National Guard’s 176th Wing, which includes three HH-60 and HC-130 rescue
squadrons and two C-17 airlift squadrons.113
Eielson Air Force Base. Eielson Air Force Base is an Air Force installation located near
Fairbanks, Alaska. It occupies approximately 24,900 acres, and hosts the 354th Operations Group,
which includes two F-35 fighter squadrons and one F-16 squadron.114

110 Note that not all of this acreage may be in active use. “FY2022 Base Structure Report,” Office of the Assistant
Secretary of Defense for Sustainment, available for download at https://www.acq.osd.mil/eie/BSI/BEI_Library.html.
“1st Infantry Brigade, 11th Airborne Division,” 11th Airborne Division, at https://11thairbornedivision.army.mil/Units/
1st-Infantry-Brigade/; “1-25 Attack/Reconnaissance Battalion,” U.S. Army Alaska, at https://home.army.mil/alaska/
index.php/USARAK-units/1-25-arb ; and “1-52 General Support Aviation Battalion,” U.S. Army Alaska, at
https://home.army.mil/alaska/index.php/USARAK-units/1-52d-gsab.
111 “FY2022 Base Structure Report.” Midcourse missile defense refers to the destruction of incoming ballistic missiles
while they are outside the atmosphere at the highest point in their trajectory (the ‘midcourse’); see “Ground-Based
Interception,” Center for Strategic and International Studies, at https://missilethreat.csis.org/defsys/gbi/ for more
information.
112 “49th Missile Defense Battalion,” U.S. Army Alaska, at https://home.army.mil/alaska/index.php/fort-greely/
unitstenants/49th-missile-defense-battalion ; “59th Signal,” U.S. Army Alaska, at https://home.army.mil/alaska/
index.php/fort-greely/unitstenants/59th-signal-nec; “Cold Regions Test Center,” U.S. Army Test and Evaluation
Command, at https://www.atec.army.mil/crtc/.
113 “FY2022 Base Structure Report.” “3rd Wing Units,” 3rd Wing, at https://www.jber.jb.mil/Units/3wg/ and “176th
Wing Units,” 176th Wing, at https://www.176wg.ang.af.mil/Units/.
114 “FY2022 Base Structure Report,” and “354th Operations Group,” Eielson Air Force Base, at
https://www.eielson.af.mil/About-Us/Units/354th-Operations-Group/.
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Clear Space Force Station. Clear Space Force Station is a Space Force installation located about
75 miles southwest of Fairbanks, AK. It occupies approximately 11,400 acres, and hosts the 13th
and 213th Space Warning Squadrons, which provide missile warning and defense as well as space
domain awareness.115
Other sites. In addition to the five installations detailed above, Alaska is home to the Northern
Warfare Training Center, an Army training site in Black Rapids, AK that provides training for
cold weather and mountain environments; the COBRA DANE L-band missile defense radar site
located in Shemya, AK; and several auxiliary airfields, including Eareckson Air Station in
Shemya, AK.116
Washington
Joint Base Lewis-McChord (JBLM). JBLM is a joint Army-Air Force installation, consisting of
a main base area, located about nine miles southwest of Tacoma, WA and the Yakima Training
Center, located near Yakima, WA. The main base area occupies approximately 87,000 acres,
while the Yakima Training Center occupies approximately 323,000 acres.117 JBLM serves as the
headquarters for the Army’s I Corps, which encompasses about 44,000 soldiers in the Indo-
Pacific region. Army units based at JBLM include the 7th Infantry Division, the 1st Multi-Domain
Task Force, and the 5th Security Force Assistance Brigade.118 JBLM also hosts the Air Force’s
62nd and 446th Airlift Wings (Reserve), which together include six C-17 airlift squadrons, as well
as the Western Air Defense Sector, a Washington Air National Guard unit responsible for regional
air defense operations.119 JBLM’s Yakima Training Center provides a large, versatile training area
in a high desert environment, including 25 separate ranges.120
Naval Base Kitsap. Naval Base Kitsap is a Navy installation on the Kitsap Peninsula in
Washington. It occupies approximately 12,000 acres and hosts a wide array of facilities and
tenant commands.121 Significant units and capabilities at Naval Base Kitsap include: two Nimitz-
class aircraft carriers (USS Nimitz and USS Theodore Roosevelt); three submarine squadrons (two
ballistic and guided missile squadrons comprised of Ohio-class submarines and one development

115 “FY2022 Base Structure Report,” and Senior Master Sgt. Julie Avey,“Alaska welcomes newest Space Force Station
in Renaming of Clear,” 168th Wing Public Affairs, June 16, 2021, at https://ak.ng.mil/Media/News/Article/2661907/
alaska-welcomes-newest-space-force-station-in-renaming-of-clear/.
116 “Northern Warfare Training Center,” U.S. Army Alaska, at https://home.army.mil/alaska/index.php/USARAK-
units/USARAK-ASC/NWTC; “Cobra Dane,” CSIS Missile Defense Project, June 7, 2021 at
https://missilethreat.csis.org/defsys/cobra-dane/; 2nd Lt Andrew Harris, “Tail End of the Chain, Tip of the Sword:
Eareckson Air Station,” at https://www.jber.jb.mil/News/News-Articles/Article/291929/tail-end-of-the-chain-tip-of-
the-sword-eareckson-as/.
117 “FY2022 Base Structure Report.” “History,” Joint Base Lewis-McChord, at https://home.army.mil/lewis-
mcchord/index.php/about/history.
118 “I Corps,” U.S. Army, at https://www.army.mil/icorps#org-about . “7th Infantry Division,” U.S. Army, at
https://www.army.mil/7thid#org-about. Thomas Brading, “1st Multi-Domain Task Force,” U.S. Army News Service,
February 1, 2021 at https://www.army.mil/article/242849/first_multi_domain_task_force_plans_to_be_centerpiece_
of_army_modernization, and Thomas Brading, “5th SFAB: More missions, fixed Indo-Pacific presence ahead,”
February 25, 2021 at https://www.army.mil/article/243702/5th_sfab_more_missions_fixed_indo_pacific_presence_
ahead.
119 “62nd Airlift Wing,” U.S. Air Force, at https://www.mcchord.af.mil/Units/ “446th Airlift Wing,” U.S. Air Force, at
https://www.446aw.afrc.af.mil/Units/446th-AW-Units/, and “Western Air Defense Sector – About Us,” Western Air
Defense Sector, at https://www.wads.ang.af.mil/About-Us/.
120 “Yakima Training Center,” Joint Base Lewis-McChord, at https://home.army.mil/lewis-mcchord/index.php/units-
tenants/yakima-training-center.
121 “Naval Base Kitsap,” Commander, Navy Region Northwest, at https://cnrnw.cnic.navy.mil/Installations/
NAVBASE-Kitsap/.
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squadron comprised of Seawolf-class submarines); one unmanned undersea vehicle (UUV)
development squadron; the Puget Sound Naval Shipyard and Intermediate Maintenance Facility
(a Navy-owned and operated shipyard that maintains, upgrades, and retires naval vessels; the
shipyard also includes Trident Refit Facility Bangor, which maintains and upgrades Indo-Pacific-
based ballistic missile submarines); Strategic Weapons Facility Pacific (a facility that stores,
maintains, and upgrades submarine-based nuclear weapons); and Manchester Fuel Depot (the
largest underground DOD fuel storage facility on the West Coast, with an average annual
throughput of 2.3 million barrels of fuel).122
Naval Station Everett. Naval Station Everett is a Navy installation located in Everett, WA. The
main base occupies approximately 217 acres, but the installation also includes the following
noncontiguous areas: Naval Radio Station Jim Creek (responsible for communication with
submarines operating in the Pacific); Naval Facility Pacific Beach (a training facility for naval
aviators); and Naval Family Support Complex Smokey Point (a facility for family and morale,
welfare, and recreation activities).123 Naval Station Everett is the homeport for seven Arleigh
Burke-class guided missile destroyers and two Coast Guard vessels (a coastal patrol boat and a
buoy tender).124
Naval Air Station Whidbey Island. Naval Air Station Whidbey Island is a Navy installation
located near Oak Harbor, WA. It occupies approximately 7,200 acres, and hosts thirteen EA-18
electronic attack squadrons, five P-8 maritime patrol squadrons, two P-3 maritime patrol
squadrons, and one EP-3 reconnaissance squadron.125
Fairchild Air Force Base. Fairchild Air Force Base is an Air Force installation located about 12
miles west of Spokane, WA. It occupies approximately 4,300 acres, and hosts the Air Force’s 92nd
Air Refueling Wing and the Washington Air National Guard’s 141st Air Refueling Wing, which
operate KC-135 refueling aircraft.126

122 Ibid., “Submarine Group 19”, Commander, Submarine Force, U.S. Pacific Fleet, at https://www.csp.navy.mil/
css19/; “Submarine Development Squadron 5”, Commander, Submarine Force, U.S. Pacific Fleet, at
https://www.csp.navy.mil/csds5/Submarines/ “Strategic Weapons Facility Pacific,” U.S. Navy, at
https://www.ssp.navy.mil/about/locations.html “Fleet Logistics Center Puget Sound,” Naval Supply Systems
Command, at https://www.navsup.navy.mil/NAVSUP-Enterprise/NAVSUP-FLC-Puget-Sound/About-FLC-Puget-
Sound/.
123 “FY2022 Base Structure Report,” and “Naval Station Everett,” Commander, Navy Region Northwest, at
https://cnrnw.cnic.navy.mil/Installations/NS-Everett/About/Installation-Guide/;
124 “Homeported Ships,” Commander, Navy Region Northwest, at https://cnrnw.cnic.navy.mil/Installations/NS-Everett/
About/Homeported-Ships/
125 “FY 2022 Base Structure Report,” “Patrol and Reconnaissance Wing 10,” Commander, Navy Region Northwest, at
https://cnrnw.cnic.navy.mil/Installations/NAS-Whidbey-Island/About/Aviation-Commands/Patrol-And-
Reconnaissance-Wing-10/ and “Electronic Attack Wing,” Commander, Navy Region Northwest, at
https://cnrnw.cnic.navy.mil/Installations/NAS-Whidbey-Island/About/Aviation-Commands/Electronic-Attack-Wing/,
and “P-3C Orion,” Naval Air Systems Command, at https://www.navair.navy.mil/product/P-3C-Orion.
126 “FY2022 Base Structure Report,” “Units,” Fairchild Air Force Base, at https://www.fairchild.af.mil/About/Units/
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California127
Naval Air Station Lemoore. Naval Air Station Lemoore is a Navy installation located about 30
miles south of Fresno, CA. It occupies approximately 40,000 acres, and hosts three F-35 fighter
squadrons and thirteen F/A-18 fighter squadrons.128
Naval Base Ventura County. Naval Base Ventura County is a Navy installation located
approximately 55 miles west of Los Angeles in Ventura County, CA. It is comprised of the three
operating areas of Point Mugu, Port Hueneme, and San Nicolas Island, which together occupy
approximately 19,400 acres. Significant units, facilities, and capabilities at Naval Base Ventura
County include four E-2/D command and control squadrons, the 30th Naval Construction
Regiment (the Pacific ‘Seabees’), Unmanned Surface Vessel (USV) Division One, and the Point
Mugu Sea Range (a 36,000 square mile area for testing missiles, free-fall weapons, and electronic
warfare systems).129
Naval Base Coronado. Naval Base Coronado is a Navy installation in San Diego, CA. It is
comprised of eight constituent sites: Naval Air Station North Island, Coronado; Naval
Amphibious Base, Coronado; Naval Outlying Landing Field, Imperial Beach; Naval Auxiliary
Landing Field, San Clemente Island; Silver Strand Training Complex-South; Camp Michael
Monsoor Mountain Warfare Training Center; Camp Morena; and the Remote Training Site,
Warner Springs. Together, these occupy over 57,000 acres and host a wide array of units and
tenant commands, including sixteen helicopter squadrons, two fixed-wing squadrons, two Nimitz-
class aircraft carriers, four Sea-Air-Land (SEAL) teams, and Commander, Naval Special Warfare
Command (SPECWAR).130
Naval Base San Diego. Naval Base San Diego is a Navy installation in San Diego, CA. It
occupies approximately 1,600 acres, and serves as the homeport for most of the Naval Surface
Force, U.S. Pacific Fleet (SURFPAC).131 In addition to 56 SURFPAC vessels (including
destroyers, cruisers, littoral combat ships, amphibious transport docks, and other warships) Naval
Base San Diego is also the homeport of the hospital ship USNS Mercy.
Naval Base Point Loma. Naval Base Point Loma is a Navy installation in San Diego, CA. It
occupies approximately 1,100 acres and hosts several significant units and tenant commands.
These include one submarine squadron (which includes four Los Angeles-class attack
submarines), a floating dry dock (used to service submarines and smaller vessels), Commander

127 Owing to the unique scale and diversity of defense infrastructure in California (and in keeping with the definition of
the Indo-Pacific region adopted by this report), several major installations that do not directly or specifically support
operations in the Indo-Pacific region have been excluded from this section (e.g., Edwards Air Force Base, Naval Air
Weapons Station China Lake).
128 “Naval Air Station Lemoore,” Commander, Navy Region Southwest, at https://cnrsw.cnic.navy.mil/Installations/
NAS-Lemoore/.
129 “Naval Base Ventura County,” Commander, Navy Region Southwest, at https://cnrsw.cnic.navy.mil/Installations/
NAVBASE-Ventura-County/About/; “Navy Cuts Ribbon on Unmanned Vehicle Testing Facilities,” Naval Sea
Systems Command, at https://www.navsea.navy.mil/Media/News/Article/2872980/navy-cuts-ribbon-on-unmanned-
vehicle-testing-facilities-at-port-hueneme/; “Point Mugu,” Naval Air Systems Command, at
https://www.navair.navy.mil/PtMugu.
130 “Naval Base Coronado,” Commander, Navy Region Southwest, at https://cnrsw.cnic.navy.mil/Installations/
NAVBASE-Coronado/.
131 “Naval Base San Diego,” Commander, Navy Region Southwest, at https://cnrsw.cnic.navy.mil/Installations/
NAVBASE-San-Diego/.
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U.S. 3rd Fleet, Naval Information Warfare Systems Command (formerly known as SPAWAR), and
Naval Mine and Anti-Submarine Warfare Command.132
Marine Corps Air Station Miramar. Marine Corps Air Station Miramar is a Marine Corps
installation in San Diego, CA. It occupies approximately 22,880 acres and hosts the 3rd Marine
Aircraft Wing’s Marine Aircraft Groups 11 and 16, which together include two F/A-18C fighter
squadrons, one F-35C fighter squadron, one KC-130 tactical aerial refueling squadron, four V-22
squadrons, and four CH-53 heavy helicopter squadrons.133
Marine Corps Base Camp Pendleton. Marine Corps Base Camp Pendleton is a Marine Corps
installation located approximately 38 miles north of San Diego, CA. It occupies approximately
125,000 acres, and serves as the headquarters of I Marine Expeditionary Force (MEF). I MEF
subordinate commands and units based at Camp Pendleton include the 1st Marine Division, the 1st
Marine Logistics Group, and the 3rd Marine Aircraft Wing’s Marine Aircraft Group 39 (which
includes four attack helicopter squadrons and two V-22 squadrons).134
Beale Air Force Base. Beale Air Force Base is an Air Force installation located approximately 45
miles north of Sacramento, CA. It occupies approximately 22,450 acres, and hosts the 9th
Reconnaissance Wing (which operates U-2 reconnaissance aircraft and RQ-4 reconnaissance
unmanned aerial vehicles) and the Air Force Reserve’s 940th Air Refueling Wing (which includes
a squadron of KC-135R aerial refueling aircraft).135 Beale Air Force Base is also home to the
Space Force’s 7th Space Warning Squadron, which operates an Upgraded Early Warning Radar
system to detect and characterize sea-launched or intercontinental ballistic missile launches
targeting North America.136
Travis Air Force Base. Travis Air Force Base is an Air Force installation located approximately
three miles east of Fairfield, CA. It occupies approximately 6,440 acres, and handles more cargo
and passenger traffic than any other air base in the United States.137 It hosts the 60th Air Mobility
Wing (which includes one C-17 airlift squadron, one C-5 airlift squadron, and two KC-10
refueling squadrons) and the Air Force Reserve’s 349th Air Mobility Wing (which includes one C-
17 airlift squadron, one C-5 airlift squadron, and two KC-10 refueling squadrons).138
Vandenberg Space Force Base. Vandenberg Space Force Base is a Space Force installation
located in Santa Barbara County, CA. It occupies approximately 99,600 acres, and provides space
launch and range capabilities for DOD, other U.S. government agencies, and commercial
partners. Vandenberg Space Force Base is the home of Space Launch Delta 30, which operates

132 “FY2022 Base Structure Report,” “History – Naval Base Point Loma,” Commander, Navy Region Southwest , at
https://cnrsw.cnic.navy.mil/Installations/NAVBASE-Point-Loma/About/History/; and https://www.navy.mil/Press-
Office/News-Stories/Article/3134642/css-11-welcomes-peruvian-submarine-to-san-diego/.
133 “FY2022 Base Structure Report,” and “3rd Marine Aircraft Wing,” 3rd Marine Aircraft Wing, at
https://www.3rdmaw.marines.mil/.
134 “Introduction,” MCB Camp Pendleton, at https://www.pendleton.marines.mil/Main-Menu/Introduction/; and
“Marine Aircraft Group 39,” 3rd Marine Aircraft Wing, at https://www.3rdmaw.marines.mil/Units/MAG-39/
135 “FY2022 Base Structure Report” “Units,” Beale Air Force Base, available at https://www.beale.af.mil/Library/
Units/.
136 “7th Space Warning Squadron Fact Sheet,” Beale Air Force Base, available at https://www.beale.af.mil/Library/
Fact-Sheets/Display/Article/279997/7th-space-warning-squadron/.
137 “FY2022 Base Structure Report,” and “Travis Air Force Base,” U.S. Air Force, at https://www.travis.af.mil/
Information/.
138 “FY2022 Base Structure Report,” and “Travis Air Force Base,” U.S. Air Force, at https://www.travis.af.mil/
Information/; and “349th Air Mobility Wing Fact Sheet,” 349th Air Mobility Wing, at https://www.349amw.afrc.af.mil/
About-Us/Fact-Sheets/Display/Article/690252/349th-air-mobility-wing-afrc/.
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sixteen on-site launch facilities and complexes.139 Vandenberg Space Force Base also hosts
ground-based interceptors to provide midcourse ballistic missile defense for western North
America.140
Hawaii
Joint Base Pearl Harbor-Hickam (JBPH-H). JBPH-H is a joint Navy-Air Force installation
located on Oahu, HI. It occupies approximately 27,000 acres, and serves as the headquarters for
U.S. Indo-Pacific Command, U.S. Pacific Fleet, U.S. Pacific Air Forces, and Defense Logistics
Agency-Indo-Pacific.141 JBPH-H is the homeport for approximately 25 Navy vessels (including
ten destroyers and cruisers and thirteen attack submarines); it also hosts the Air Force’s 15th Wing
(which includes one C-17 airlift squadron, one C-37 airlift squadron, and one F-22 fighter
squadron) and the Hawaii Air National Guard’s 154th Wing (which includes one F-22 fighter
squadron, one KC-135 refueling squadron, and one C-17 airlift squadron).142 Other significant
facilities and capabilities at JBPH-H include the Pearl Harbor Naval Shipyard and Intermediate
Maintenance Facility (a Navy-owned and operated shipyard that maintains, upgrades, and retires
naval vessels), the 613th Air Operations Center (which provides command and control for Air
Force operations throughout the Indo-Pacific region), and the Red Hill Bulk Fuel Facility (a large
underground fuel storage facility which DOD is currently defueling in response to the JBPH-H
Drinking Water Emergency).143
Schofield Barracks. Schofield Barracks is an Army installation located in Honolulu, HI. It
occupies approximately 16,000 acres, and is the home of the Army’s 25th Infantry Division.144
Fort Shafter. Fort Shafter is an Army installation located in Honolulu, HI. It occupies
approximately 585 acres, and is the headquarters of U.S. Army Pacific (ARPAC). Other
significant units and facilities at Fort Shafter include the U.S. Army Corps of Engineers Pacific
Ocean Division, the 94th Army Air and Missile Defense Command, and the 8th Theater
Sustainment Command.145
Wheeler Army Airfield. Wheeler Army Airfield is an Army installation located in Honolulu, HI.
It occupies approximately 1,400 acres, and hosts the Army Garrison Hawaii headquarters as well
as the Hawaii Air National Guard’s 298th Air Defense Group.146
Pacific Missile Range Facility (PMRF) Barking Sands. PMRF Barking Sands is a Navy
installation located approximately five miles outside of Kekaha on the island of Hawaii, HI. It

139 “Vandenberg Space Force Base,” Vandenberg Space Force Base, at https://www.vandenberg.spaceforce.mil/About-
Us/History/.
140 “Vandenberg Launches GBI,” Vandenberg Space Force Base, at https://www.afspc.af.mil/News/Photos/igphoto/
2000398793/.
141 “About,” Commander, Navy Region Hawaii, at https://cnrh.cnic.navy.mil/Installations/JB-Pearl-Harbor-Hickam/
About/.
142 “Fleet Information,” Commander, Navy Region Hawaii, at https://cnrh.cnic.navy.mil/About/Fleet-Information/;
“15th Wing Fact Sheet,” 15th Wing, at https://www.15wing.af.mil/About-Us/Fact-Sheets/Display/Article/376262/15th-
wing/.
143 “613th Air Operations Center,” Pacific Air Forces, at https://www.pacaf.af.mil/Info/Fact-Sheets/Display/Article/
909886/613th-air-operations-center/.
144 “FY2022 Base Structure Report”, “25th Infantry Division,” U.S. Army Hawaii, at https://home.army.mil/hawaii/
index.php/units-tenants/25thID.
145 “FY2022 Base Structure Report.” “Tenant Units,” U.S. Army Hawaii, at https://home.army.mil/hawaii/index.php.
146 “Wheeler Field,” State of Hawaii Aviation, at https://aviation.hawaii.gov/airfields-airports/oahu/wheeler-field/.
“Tenant Units,” U.S. Army Hawaii, at https://home.army.mil/hawaii/index.php.
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occupies approximately 2,500 acres of land on Hawaii, but the range encompasses over 1,100
square miles of instrumented ocean and 42,000 square miles of controlled airspace. PMRF
Barking Sands is the world’s largest instrumented sea range, supporting training and RDT&E
activities involving surface, undersea, air, and space-based weapons systems.147
Marine Corps Base Hawaii. Marine Corps Base Hawaii is a Marine Corps installation located
approximately 12 miles northeast of downtown Honolulu, HI. It occupies approximately 3,200
acres, and hosts the 3rd Marine Littoral Regiment, 1st Battalion 12th Marines, 3rd Radio Battalion
III MEF, and Marine Aircraft Group 24 (which includes one light attack helicopter squadron, two
MV-22 squadrons, and one UAV squadron).148
Wake Island
Wake Island Airfield. Wake Island Airfield is an Air Force installation located on Wake Atoll (an
unincorporated U.S. territory approximately 2,100 nautical miles west of Honolulu, HI). It
occupies approximately 2,600 acres and hosts 11th Air Force, Detachment 1-Pacific Air Forces
Regional Support Center. Wake Island Airfield primarily supports trans-pacific military air traffic
and missile test activities.149
Guam and the Northern Mariana Islands
Naval Base Guam. Naval Base Guam is a Navy installation located in Guam. As with other
DOD sites in Guam and the Northern Mariana Islands, Naval Base Guam is managed as part of
Joint Region Marianas.150 Naval Base Guam encompasses six noncontiguous sites across the
island: Barrigada, North Finegayan, Ordnance Annex, Orote Point, Polaris Point, and Tenjo and
Sasa Valley. The installation hosts one submarine squadron (consisting of five Los Angeles-class
attack submarines), two submarine tenders, and Navy Expeditionary Forces Command Pacific
(CTF-75).151
Marine Corps Base Camp Blaz. Marine Corps Camp Blaz is a Marine Corps installation located
in Guam and managed as part of Joint Region Marianas. It is the Marine Corps’ newest
installation, and will host Marine Corps forces currently stationed at Okinawa beginning in the
mid-2020s (expected to include a Marine Expeditionary Brigade (MEB) command element, a
Marine Infantry Regiment, a Combat Logistics Battalion, and an Air Combat Element). Camp
Blaz currently hosts an Army Terminal High Altitude Area Defense (THAAD) battery.152
Andersen Air Force Base. Andersen Air Force Base is an Air Force installation located in Guam
and managed as part of Joint Region Marianas. It hosts the 36th Wing, which supports rotational

147 “FY 2022 Base Structure Report.” “PMRF Barking Sands,” Commander, Navy Region Hawaii, at
https://cnrh.cnic.navy.mil/Installations/PMRF-Barking-Sands/.
148 “FY2022 Base Structure Report.” “Mission,” Marine Corps Base Hawaii, at https://www.mcbhawaii.marines.mil/
Unit-Home/Mission/.
149 “Wake Island,” 15th Wing, at https://www.15wing.af.mil/Units/11th-AF-Det-1-Wake-Island/. “FY2022 Base
Structure Report.”
150 “Joint Region Marianas,” Joint Region Marianas, at https://jrm.cnic.navy.mil/.
151 “Submarine Squadron 15,” Commander, Submarine Forces, U.S. Pacific Fleet, at https://www.csp.navy.mil/css15/.
152 Wyatt Olson, “Guam’s THAAD Missile Defense Battery will relocate to new Marine Corps Base,” Stars and
Stripes, May 10, 2022 at https://www.stripes.com/theaters/asia_pacific/2022-05-10/guam-us-army-thaad-missile-
defense-battery-marine-corps-camp-blaz-5952276.html
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bomber deployments (B-1 and B-52 aircraft) and regional contingency responses, as well as the
Navy’s Helicopter Sea Combat Squadron 25 (consisting of MH-60S helicopters).153
The Marshall Islands, Micronesia, and Palau
U.S. Army Garrison-Kwajalein Atoll. U.S. Army Garrison-Kwajalein Atoll is an Army
installation located on Kwajalein Atoll in the Republic of the Marshall Islands. Its main site
occupies approximately 1,360 acres, and hosts the Ronald Reagan Ballistic Missile Defense Test
Site, a Major Range and Test Base Facility (MRTBF) supporting RDT&E activities for ballistic
missile defense systems, strategic systems, and space tracking systems.154
Tactical Mobile Over-the-Horizon Radar (Republic of Palau). The Air Force is constructing a
site in the Republic of Palau to support the installation of a Tactical Mobile Over-the-Horizon
Radar system. Construction should conclude in 2026.155
Japan (Mainland)
Camp Zama (including Sagami General Depot and Yokohama North Dock). Camp Zama is
an Army installation located about 25 miles southwest of Tokyo, Japan. It occupies approximately
578 acres, and serves as the headquarters for U.S. Army Japan, U.S. Army Garrison Japan, I
Corps (Forward), and the U.S. Army Corps of Engineers Japan District.156 It also hosts Army
Aviation Battalion Japan (which operates UH-60L helicopters and UC-35 fixed-wing aircraft), the
38th Air Defense Artillery Brigade, the 35th Combat Sustainment Support Battalion, the 78th
Signal Battalion, the 311th Military Intelligence Battalion, the 403rd Logistics Readiness Center,
and the 836th Transportation Battalion.157
Shariki and Kyogamisaki Communications Sites. Shariki Communications Site and
Kyogamisaki Communications Site are Army installations, located respectively in northern and
western Honshu, Japan. Each hosts an Army Navy Transportable Radar Surveillance and Control
Model 2 (AN/TPY-2) system, used to detect and track ballistic missile threats to the Indo-Pacific
and the continental United States.158
Fleet Activities Yokosuka. Fleet Activities Yokosuka is a Navy installation located about 43
miles south of Tokyo, Japan. It occupies approximately 568 acres, and hosts a number of surface
warships, including a Nimitz-class aircraft carrier (the USS Ronald Reagan, currently the Navy’s
only forward deployed carrier), a destroyer squadron (consisting of nine Arleigh Burke-class
guided-missile destroyers), and three Ticonderoga-class guided missile cruisers.159 The

153 “Units,” Andersen Air Force Base, at https://www.andersen.af.mil/Units/.
154 “Mission,” U.S. Army Garrison – Kwajalein Atoll, at https://home.army.mil/kwajalein/index.php/about/mission.
155 See “Contracts for Dec. 28, 2022,” Department of Defense, at https://www.defense.gov/News/Contracts/Contract/
Article/3255710/.
156 “FY2022 Base Structure Report.”
157 “Honshu,” U.S. Army Japan, at https://www.usarj.army.mil/misc/map_honshu/.
158 Jason Cutshaw, “Shariki Soldiers Defend Homeland, Allies,” U.S. Army, October 8, 2019, at https://www.army.mil/
article/227673/shariki_soldiers_defend_homeland_allies; Charlie Maib, “Kyogamisaki Communications Site,” U.S.
Army, March 7, 2022, at https://www.army.mil/article/254485/kyogamisaki_communications_site_knife_edge_of_
freedom.
159 “Destroyer Squadron 15,” Naval Surface Force, U.S. Pacific Fleet, at https://www.surfpac.navy.mil/cds15/; “Ships,”
Naval Surface Force, U.S. Pacific Fleet, at https://www.surfpac.navy.mil/Ships/.
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installation is also home to the U.S. Naval Ship Repair Facility and Japan Regional Maintenance
Center.160
Fleet Activities Sasebo. Fleet Activities Sasebo is a Navy installation located in western Kyushu,
Japan. It occupies approximately 150 acres, and hosts a number of surface warships, including an
amphibious squadron (consisting of one America-class amphibious assault ship, two San Antonio-
class amphibious transport docks, and two Whidbey Island-class dock landing ships) and a mine
countermeasure squadron (consisting of four Avenger-class mine countermeasure ships).161
Naval Air Facility Atsugi. Naval Air Facility Atsugi is a joint U.S. Navy-Japan Maritime Self
Defense Force installation located about 20 miles southwest of Tokyo, Japan. It occupies
approximately 1,234 acres, and serves as a support base for certain Carrier Air Wing Five aircraft
(including a helicopter maritime strike squadron and a helicopter sea combat squadron).162
Marine Corps Air Station Iwakuni. Marine Corps Air Station Iwakuni is a Marine Corps
installation located in southern Honshu, Japan. It occupies approximately 7,100 acres, and hosts
two F-35 fighter squadrons and one KC-130 aerial refueling squadron. It also serves as a support
base for most Carrier Air Wing 5 aircraft (including four F/A-18 fighter squadrons, one EA-18
electronic attack squadron, and one E-2D command and control squadron).163
Yokota Air Base. Yokota Air Base is a joint U.S. Air Force and Japan Air Self-Defense Force
installation located in the greater Tokyo metropolitan area, Japan. It occupies approximately
1,750 acres, and serves as the headquarters for U.S. Forces Japan and the Fifth Air Force.164
Yokota Air Base also hosts the 374th Airlift Wing, which includes one C-130J squadron and one
squadron operating UH-1N helicopters and C-12J aircraft.165
Misawa Air Base. Misawa Air Base is an Air Force installation located in northern Honshu,
Japan. It occupies approximately 3,860 acres, and hosts the 35th Fighter Wing, which includes two
F-16 fighter squadrons.166
Japan (Okinawa)
Army Garrison Okinawa. Army Garrison Okinawa encompasses a number of noncontiguous
Army installations on the island of Okinawa, including Torii Station, Fort Buckner, Tengan Pier,
Kuwae Depot Chimuwan, White Beach Fuel Tank Farms, and Naha Military Port. The garrison
supports logistical functions (particularly fuel storage and distribution) and can provide regional
contingency support.167

160 “U.S. Naval Ship Repair Facility and Japan Regional Maintenance Center,” U.S. Navy, at https://www.srf.navy.mil/.
161 “History,” Commander, Fleet Activities Sasebo, at https://cnrj.cnic.navy.mil/Installations/CFA-Sasebo/About/
History/.
162 “FY2022 Base Structure Report”, and “Carrier Air Wing 5 – Squadrons,” Naval Air Force, U.S. Pacific Fleet at
https://www.airpac.navy.mil/Organization/Carrier-Air-Wing-CVW-5/Squadrons/.
163 “History of the Iwakuni Air Station,” U.S. Marine Corps, p. 2, at https://www.mcasiwakuni.marines.mil/Portals/112/
Docs/about/About_Iwakuni.pdf?ver=2020-03-04-205157-940. Note that the acreage given on the official MCAS
Iwakuni website differs from that given by the “FY2022 Base Structure Report,” which lists 7,110.64 acres for the
installation. A number of other sources agree with a figure of 1,300-1,400 acres (including Military One Source at
https://installations.militaryonesource.mil/in-depth-overview/marine-corps-air-station-iwakuni).
164 “FY2022 Base Structure Report.”
165 “Units,” Yokota Air Base, at https://www.yokota.af.mil/About-Us/Units/.
166 “FY2022 Base Structure Report”. “35th Fighter Wing,” Misawa Air Base, at https://www.misawa.af.mil/About-Us/
Fact-Sheets/Display/Article/773149/35th-fighter-wing/.
167 “History,” U.S. Army Garrison Okinawa, at https://home.army.mil/okinawa/index.php/about/history.
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Marine Corps Base Camp Butler. Marine Corps Base (MCB) Camp Butler encompasses
contiguous and noncontiguous Marine Corps installations (including Camps Foster, Lester,
Courtney, McTureous, Kinser, Hansen, Schwab, and Gonsalves) that together occupy
approximately 40,000 acres on the island of Okinawa.168 MCB Camp Butler hosts the III Marine
Expeditionary Force (III MEF), a Marine Air-Ground Task Force and the only permanently
forward-deployed Marine Expeditionary Force. Subordinate units of III MEF stationed at MCB
Camp Butler include the 3rd Marine Division, 1st Marine Aircraft Wing, 3rd Marine Logistics
Group, 3rd Marine Expeditionary Brigade, 31st Marine Expeditionary Unit and III MEF
Information Group. Other significant facilities and capabilities located at MCB Camp Butler
include the Jungle Warfare Training Center and other training areas and live fire ranges.169
Marine Corps Air Station Futenma. Marine Corps Air Station (MCAS) Futenma is a Marine
Corps installation located in southern Okinawa. It occupies approximately 1,200 acres, and hosts
two medium tilt-rotary squadrons (operating CH-53E heavy-lift helicopters, AH-1Z Viper attack
helicopters, and UH-1Y utility helicopters as well as MV-22 tiltrotor aircraft) and support from
Marine Aircraft Group 36.170
Kadena Air Base. Kadena Air Base is an Air Force installation located near Okinawa City,
Okinawa, Japan. It occupies approximately 4,900 acres, and hosts the 18th Wing, subordinate
units of which include a KC-135 refueling squadron, an E-3 AWACS airborne air control
squadron, and an HH-60 rescue squadron.171 Until November 2022, Kadena also hosted two F-
15D/D fighter squadrons; as of this writing, the Air Force is rotationally deploying F-22 fighter
aircraft from Joint Base Elmendorf-Richardson, Alaska.172
Republic of Korea
Camp Humphreys. Camp Humphreys is an Army installation located in Pyeongtaek, South
Korea (about 40 miles south of Seoul). Camp Humphreys occupies approximately 3,500 acres,
and serves as the headquarters for U.S. Forces Korea, the Eighth Army, and U.S. Marine Corps
Forces Korea. 173 Camp Humphreys also hosts the 2nd Infantry Division/Republic of Korea-U.S.
Combined Division, the Army’s only permanently forward-stationed division (major units include
a rotational armored brigade combat team, two field artillery brigades, and a combat aviation
brigade).174
U.S. Army Garrison Daegu (Camps Henry, Walker, George and Carroll; Busan Pier 8). U.S.
Army Garrison Daegu encompasses five significant Army installations in eastern South Korea:
Camps Henry, Walker, and George (located in the Daegu metropolitan area); Camp Carroll
(located in North Gyeongsan province); and Busan Pier 8 (located in the Busan metropolitan

168 “Introduction – Marine Corps Base Camp Butler,” DOD Environment, Safety & Occupational Health Network and
Information Exchange, at https://www.denix.osd.mil/awards/denix-files/sites/12/2018/03/CRM-LI-USMC-Butler-
Narrative-508C.pdf. Note that the FY2022 Base Structure Report does not provide information for the entire MCB
Camp Butler site.
169 “Marine Corps Camp Butler,” Marine Corps Camp Butler, at https://www.mcbbutler.marines.mil/.
170 “About,” 1st Marine Air Wing, at https://www.1stmaw.marines.mil/Unit-Home/About/.
171 “FY2022 Base Structure Report”, and “18th Wing Fact Sheet,” U.S. Air Force, at https://www.5af.pacaf.af.mil/
About-Us/Fact-Sheets/Display/Article/1483830/18th-wing/.
172 https://www.stripes.com/branches/air_force/2022-11-22/air-force-kadena-f22-raptor-rotations-8144899.html
173 “History, Camp Humphreys, at https://home.army.mil/humphreys/index.php/about/history.
174 “2nd Infantry Division (2ID)-Korea,” 2nd Infantry Division, at https://www.2id.korea.army.mil/.
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area). Significant units and capabilities include the 19th Sustainment Command (Expeditionary),
the 403rd Army Field Support Brigade-Korea, and Material Supply Center-Korea.175
U.S. Army Garrison Yongsan-Casey (K-16, Yongsan Garrison, and Camp Casey). U.S. Army
Garrison Yongsan-Casey encompasses installations in the Seoul metropolitan area of South
Korea: the K-16 airfield, Yongsan Garrison, and Camp Casey. In accordance with the terms of
two bilateral agreements, DOD is gradually returning these sites to the South Korean government,
with many former functions and units moving to Camp Humphreys.176
Fleet Activities Chinhae. Fleet Activities Chinhae is a Navy installation in Changwon City,
South Korea. The only Navy installation in Korea, Fleet Activities Chinhae hosts U.S. Naval
Forces, Detachment Chinhae, a small detachment of approximately 300 sailors which coordinates
operations, exercises, and other institutional cooperation between the U.S. and ROK Navies.177
Marine Corps Installation Camp Mujuk. Marine Corps Installation Camp Mujuk is a Marine
Corps installation located in Pohang, South Korea. The only Marine Corps installation in Korea,
Camp Mujuk supports rotational Marine Corps units and combined U.S.-ROK training
exercises.178
Osan Air Base. Osan Air Base is an Air Force installation located about 20 miles south of Seoul,
South Korea. It occupies approximately 1,500 acres, and serves as the headquarters of the
Seventh Air Force. Osan Air Base also hosts the 51st Fighter Wing (which includes one A-10
attack squadron and one F-16 fighter squadron) and one U-2 reconnaissance squadron from the
9th Reconnaissance Wing.179
Kunsan Air Base. Kunsan Air Base is an Air Force installation located about 7 miles west of
Gunsan City. It occupies approximately 2,549 acres, and hosts the 8th Fighter Wing (which
includes two F-16 fighter squadrons).180
The Philippines
Nine Enhanced Defense Cooperation Agreement (EDCA) Sites. Under the Enhanced Defense
Cooperation Agreement, the U.S. military has rotational access to nine defense sites across the
Philippines. Five of these installations were agreed upon in 2014 (Antonio Bautista Air Base in
Palawan, Basa Air Base in Pampanga, Fort Magsaysay in Nueva Ecija, Lumbia Airport in
Cagayan de Oro, Benito Ebuen Air Base in Cebu), while the remaining four were agreed upon in
2023 (Naval Base Camilo Osias in Sta Ana, Cagayan; Lal-lo Airport in Lal-lo, Cagayan; Camp
Melchor Dela Cruz in Gamu, Isabela and Balabac Island in Palawan).181

175 “About,” U.S. Army Garrison Gaegu, at https://www.army.mil/daegu#org-about
176 These agreements are the 2002 Land Partnership Plan (available at https://2001-2009.state.gov/documents/
organization/98126.pdf) and the 2004 Yongsan Relocation Plan (available at https://2001-2009.state.gov/documents/
organization/95894.pdf).
177 “Commander, Fleet Activities Chinhae” Commander, Navy Region Korea, at https://cnrk.cnic.navy.mil/
Installations/CFA-Chinhae/.
178 “MCI Camp Mujuk,” Marine Corps, at https://www.mcipac.marines.mil/Installations/Camp-Mujuk.
179 “Osan Air Base,” Pacific Air Forces, https://www.pacaf.af.mil/Info/Fact-Sheets/Display/Article/909898/osan-air-
base/
180 “FY2022 Base Structure Report,” and “8th Fighter Wing,” Kunsan Air Base, available at kunsan.af.mil/About-Us/
Fact-Sheets/Article/412731/8th-fighter-wing/.
181 “U.S., Philippines Cut the Ribbon on Enhanced Defense Cooperation Project,” U.S. Embassy in the Philippines, at
https://www.pacom.mil/Media/News/News-Article-View/Article/1744271/us-philippines-cut-the-ribbon-on-enhanced-
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Singapore
Navy Region Center Singapore. The U.S. Navy maintains a presence in Singapore primarily to
manage and provide logistical support for visiting surface warships (mainly at Changi Naval Base
and Sembawang shipyard). In addition, Paya Lebar Air Base hosts rotational Air Force personnel
and aircraft. Other DOD activities present in Singapore and managed through Navy Region
Center Singapore include Logistics Group Western Pacific, Naval Supply Systems Command
Fleet Logistics Center Yokosuka Site Singapore, Military Sealift Command Far East, and Defense
Contract Management Agency Singapore.182
Australia
Royal Australian Air Force (RAAF) Base Darwin and Robertson Barracks. RAAF Base
Darwin and Robertson Barracks are two Australian military installations located in the Northern
Territory. Since 2011, they have hosted a rotational U.S. Marine Air Ground Task Force known as
Marine Rotational Force-Darwin (MRF-D). MRF-D rotations are typically six months and
involve combined exercises and training with the Australian military and other regional
partners.183
RAAF Base Tindal. RAAF Base Tindal is an RAAF installation in Australia’s Northern Territory
that hosts rotational deployments of U.S. aircraft and personnel and supports the Enhanced Air
Cooperation (EAC) initiative between the RAAF and U.S. Air Force. To support its usage of the
base (which includes the rotational deployment of B-52 bomber aircraft), the United States is
currently funding construction of a new bulk fuel facility.184
Naval Communication Station Harold E. Holt. Naval Communication Station Harold E. Holt
is a naval installation jointly operated by the Royal Australian Navy (RAN) and the U.S. Navy.

defense-cooperation-agreement-project/, “Philippines, U.S. Announce Four New EDCA Sites,” Department of
Defense, February 1, 2023, ar https://www.defense.gov/News/Releases/Release/Article/3285566/philippines-us-
announce-four-new-edca-sites/, and “4 Additional EDCA Sites,” Presidential Communications Office, April 2, 2023 at
https://pco.gov.ph/news_releases/palace-4-additional-edca-sites-to-boost-ph-humanitarian-relief-operations-in-
disasters/
182 “Tenant Commands,” Commander, Navy Region Japan, at https://cnrj.cnic.navy.mil/Installations/Singapore-Area-
Coordinator/About/Tenant-Commands/.
183 See Capt. Joseph DiPietro, “Marine Rotational Force-Darwin 22 Arrives in Darwin,” U.S. Indo-Pacific Command,
March 17, 2022 at https://www.pacom.mil/Media/News/News-Article-View/Article/2970258/marine-rotational-force-
darwin-22-arrives-in-darwin/.
184 See Seth Robson, “U.S. military’s footprint is expanding in northern Australia to meet a rising
China,” Stars and Stripes, September 8, 2022, at
https://www.stripes.com/theaters/asia_pacific/2022-09-08/australia-military-construction-
projects-china-7251762.html and the “Congress funds the establishment and sustainment of
defense infrastructure through the Military Construction and Operation and Maintenance
appropriations titles. In addition, beginning in FY2021, Congress has authorized a particular set
of Indo-Pacific defense infrastructure appropriations as part of the Pacific Deterrence Initiative
(PDI), a group of regionally-focused defense investments and activities typically included as part
of the annual National Defense Authorization Act (NDAA).
Military Construction” subheading within the “Issues for Congress” section of this report.
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The site occupies approximately 5,100 acres, and broadcasts communications to Australian and
U.S. submarines using Very Low Frequency (VLF) communications.185
Other Sites. As part of the Australia-United Kingdom-U.S. (AUKUS) pact, the Royal Australian
Navy’s (RAN) HMAS Stirling naval base (located in Perth, Western Australia) will host
rotational deployments of U.S. and U.K. nuclear-powered submarines beginning in 2027. U.S.
submarines will also increase the frequency of visits to HMAS Stirling beginning in 2023.186
British Indian Ocean Territory (Diego Garcia)
Naval Support Facility Diego Garcia. Naval Support Facility Diego Garcia is a Navy
installation located on Diego Garcia, an atoll in the British Indian Ocean Territory. It occupies
approximately 6,200 acres, and its primary function is to provide logistical support for forces
operating in and around the Persian Gulf and Indian Ocean. Significant units and capabilities
based at Diego Garcia include a maritime pre-positioning squadron and detachments from the
U.S. Fleet and Industrial Supply Center, Air Mobility Command, Pacific Air Force, and the 21st
and 22nd Space Operations Squadrons (providing space domain awareness and satellite control,
respectively).187
Table A-1. U.S. Defense Sites in the Indo-Pacific
U.S.-owned, -operated, or -utilized sites included in this report
U.S.
DOD-
No.
Site Name
Location
Service
territory?
operated?
1
Fort Wainwright
Alaska
Army
Yes
Yes
2
Fort Greely
Alaska
Army
Yes
Yes
3
Joint Base Elmendorf-Richardson
Alaska
Joint (Army and
Yes
Yes
Air Force)
4
Eielson Air Force Base
Alaska
Air Force
Yes
Yes
5
Eareckson Air Station
Alaska
Air Force
Yes
Yes
6
Clear Space Force Station
Alaska
Space Force
Yes
Yes
7
Joint Base Lewis-McChord
Washington
Joint (Army and
Yes
Yes
Air Force)
8
Naval Base Kitsap
Washington
Navy
Yes
Yes
9
Naval Station Everett
Washington
Navy
Yes
Yes
10
Naval Air Station Whidbey Island
Washington
Navy
Yes
Yes
11
Fairchild Air Force Base
Washington
Air Force
Yes
Yes
12
Naval Base Ventura County
California
Navy
Yes
Yes
13
Naval Base Coronado
California
Navy
Yes
Yes

185 “FY2022 Base Structure Report”; ‘open-source’ information about NCS Harold E Holt is not widely available, but
for a basic overview, see “Raytheon Australia Commences Operations at the Naval Communications Station, Harold E.
Holt,” Raytheon Australia, November 4, 2011 https://raytheon.au.mediaroom.com/news-release-archive? item=78.
186 David Weber, “AUKUS deal: Jim Chalmers announces $8 billion HMAS Stirling naval base expansion,” Australian
Broadcasting Corporation, March 14, 2023 https://www.abc.net.au/news/2023-03-14/aukus-deal-jim-chalmers-hmas-
stirling-expansion-perth-wa/102092058 .
187 “About Diego Garcia,” Commander, Navy Region Japan, at https://cnrj.cnic.navy.mil/Installations/NSF-Diego-
Garcia/About/About-Diego-Garcia/.
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U.S.
DOD-
No.
Site Name
Location
Service
territory?
operated?
14
Naval Base San Diego
California
Navy
Yes
Yes
15
Naval Base Point Loma
California
Navy
Yes
Yes
16
Marine Corps Air Station
California
Marine Corps
Yes
Yes
Miramar
17
Marine Corps Base Camp
California
Marine Corps
Yes
Yes
Pendleton
18
Beale Air Force Base
California
Air Force
Yes
Yes
19
Travis Air Force Base
California
Air Force
Yes
Yes
20
Vandenberg Space Force Base
California
Air Force
Yes
Yes
21
Schofield Barracks
Hawaii
Army
Yes
Yes
22
Fort Shafter
Hawaii
Army
Yes
Yes
23
Wheeler Army Airfield
Hawaii
Army
Yes
Yes
24
Joint Base Pearl Harbor-Hickam
Hawaii
Joint (Navy and
Yes
Yes
Air Force)
25
Pacific Missile Range Facility,
Hawaii
Navy
Yes
Yes
Barking Sands
26
Marine Corps Base Hawaii
Hawaii
Marine Corps
Yes
Yes
27
Wake Island Airfield
Wake Island
Air Force
Yes
Yes
28
Naval Base Guam
Guam
Navy
Yes
Yes
29
Marine Corps Base Camp Blaz
Guam
Marine Corps
Yes
Yes
30
Andersen Air Force Base
Guam
Air Force
Yes
Yes
31
Army Garrison-Kwajalein Atol
Republic of the
Army
No
Yes
Marshall Islands
32
Camp Zama
Japan (Mainland)
Army
No
Yes
33
Shariki Communications Site
Japan (Mainland)
Army
No
Yes
34
Kyogamisaki Communications
Japan (Mainland)
Army
No
Yes
Site
35
Fleet Activities Yokosuka
Japan (Mainland)
Navy
No
Yes
36
Fleet Activities Sasebo
Japan (Mainland)
Navy
No
Yes
37
Naval Air Facility Atsugi
Japan (Mainland)
Navy
No
Yes
38
Marine Corps Air Station Iwakuni Japan (Mainland)
Marine Corps
No
Yes
39
Yokota Air Base
Japan (Mainland)
Air Force
No
Yes
40
Misawa Air Base
Japan (Mainland)
Air Force
No
Yes
41
Army Garrison Okinawa
Japan (Okinawa)
Army
No
Yes
42
Marine Corps Base Camp Butler
Japan (Okinawa)
Marine Corps
No
Yes
43
Marine Corps Air Station
Japan (Okinawa)
Marine Corps
No
Yes
Futenma
44
Kadena Air Base
Japan (Okinawa)
Air Force
No
Yes
45
Camp Humphreys
Republic of Korea
Army
No
Yes
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U.S.
DOD-
No.
Site Name
Location
Service
territory?
operated?
46
Army Garrison Daegu
Republic of Korea
Army
No
Yes
47
Army Garrison Yongsan-Casey
Republic of Korea
Army
No
Yes
48
Fleet Activities Chinhae
Republic of Korea
Navy
No
Yes
49
Marine Corps Installation Camp
Republic of Korea
Marine Corps
No
Yes
Mujuk
50
Osan Air Base
Republic of Korea
Air Force
No
Yes
51
Kunsan Air Base
Republic of Korea
Air Force
No
Yes
52
Antonio Bautista Air Base
The Philippines
N/A
No
No
53
Basa Air Base
The Philippines
N/A
No
No
54
Fort Magsaysay
The Philippines
N/A
No
No
55
Lumbia Airport
The Philippines
N/A
No
No
56
Benito Ebuen Air Base
The Philippines
N/A
No
No
57
Naval Base Camilo Osias
The Philippines
N/A
No
No
58
Lal-lo Airport
The Philippines
N/A
No
No
59
Camp Melchor Dela
The Philippines
N/A
No
No
60
Balabac Island
The Philippines
N/A
No
No
61
Navy Region Center Singapore
Singapore
Navy
No
No
62
Royal Australian Air Force Base
Australia
N/A
No
No
Darwin
63
Robertson Barracks
Australia
N/A
No
No
64
Royal Australian Air Force Base
Australia
N/A
No
No
Tindal
65
Naval Communications Station
Australia
Navy
No
Yes (jointly
Harold E. Holt
w/ RAN)
66
Naval Support Facility Diego
British Indian
Navy
No
Yes
Garcia
Ocean Territory
(Diego Garcia)
Source: CRS analysis of DOD information.
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Appendix B. Historical Overview of Indo-Pacific
Defense Infrastructure
U.S. defense infrastructure in what is now termed the Indo-Pacific region dates to the early 19th
century. Although only in use for four months, Fort Clatsop, the winter encampment established
by the U.S. Army’s Corps of Discovery in 1805, was the first U.S. defense facility on North
America’s Pacific coast.188 As U.S. expansion and settlement accelerated, the Army established a
number of permanent outposts in what are now the states of Oregon, Washington, and California
beginning in the 1840s and 1850s.189 The U.S. Navy also began to operate in the Pacific during
this period, although the lack of development in coastal areas (particularly prior to the 1848
acquisition of California) meant that American vessels relied mainly on foreign ports for
provisioning and repair.190
Between the end of the Mexican-American War (1848) and the Spanish-American War (1898),
the U.S. purchased Alaska (1867) and took possession of Midway Atoll (1867).191 In 1898,
expansionist sentiment and victory over Spain led to the U.S. annexation of the Republic of
Hawaii and the formerly Spanish territories of the Philippines and Guam. From an infrastructure
perspective, each of these areas quickly acquired significance. A major rationale for the
annexation of Hawaii was its importance as a refueling and supply stop for vessels transiting the
Pacific, and in 1899 the Navy established a naval station at Pearl Harbor.192 In the Philippines, the
U.S. military built or expanded a wide array of installations, including a naval base and coastal
fortifications at Subic Bay and a number of Army outposts throughout the territory.193 In Guam,
the Department of the Navy established a naval station and a Marine barracks.194

188 Fort Clatsop was established at the mouth of the Columbia River, close to what is now Astoria, OR. See “Fort
Clatsop,” National Park Service, at https://www.nps.gov/places/fort-clatsop-or.htm.
189 Examples include Camp Vancouver/Vancouver Barracks in what is now Washington and Fortress Alacatraz in what
is now California. See “Vancouver Barracks,” National Park Service, at
https://www.nps.gov/fova/learn/historyculture/vb.htm and “Fortress Alcatraz,” National Park Service, at
https://www.nps.gov/alca/learn/historyculture/fortress-alcatraz.htm.
190 This led to U.S. policy commitments such as the Tyler Doctrine (1842), which expanded the Monroe Doctrine to
cover the then-independent Kingdom of Hawai’i in part due to its importance for “the refitment and provisioning of
American vessels”. See Michael Green, By More Than Providence: Grand Strategy and American Power in the Asia-
Pacific since 1783 (New York: Columbia University Press, 2017), p. 31.
191 The Army operated a number of small forts along Alaska’s southern coast, while an initial attempt to build a coaling
station on Midway was abandoned by 1870. See Captain Richard Packer, “150 years of the Army in Alaska” Defense
Visual Information Distribution Service (DVIDS), October 31, 2017, https://www.dvidshub.net/news/253683/150-
years-army-alaska; and “A Brief History of Midway Atoll,” Papahānaumokuākea Marine National Monument,
https://www.papahanaumokuakea.gov/maritime/midway.html.
192 As one Senator put it during the annexation debate, “the Pacific is so wide that battleships cannot cross it from any
foreign naval station to the Pacific coast without recoaling, and there is no place to recoal except Hawaii.” Quoted in
Green, By More than Providence, p. 88. See also “Development of the Naval Establishment in Hawaii,” Naval History
and Heritage Command, at https://www.history.navy.mil/research/library/online-reading-room/title-list-
alphabetically/u/the-us-navy-and-hawaii-a-historical-summary/development-of-the-naval-establishment-in-hawaii.html
193 Early U.S. installations in the Philippines included Fort Stotsenburg (which would become Clark Air Base) and Fort
Santiago, the headquarters of the Army’s Philippine Department. See David L. Rosmer, An Annotated Pictorial History
of Clark Air Base (Washington, D.C.: Thirteenth Air Force Office of History, 1986), p. 38.
194 “History – Naval Base Guam,” Joint Region Marianas, at https://jrm.cnic.navy.mil/Installations/NAVBASE-
Guam/About/History/.
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Given the centrality of the European theater to World War I (1914-18), the role played by U.S.
Indo-Pacific defense infrastructure was minimal.195 However, many of the war’s military
innovations and geopolitical consequences influenced regional infrastructure developments in the
1920s and 30s.196 For U.S. planners, Pacific defense sites during the interwar period played two
major roles: they enabled the Navy to operate in the region; and they offered a degree of
protection to U.S. territories and commercial interests. As conflict with Japan became more
plausible in the late 1930s and early 1940s, the U.S. military increased the resources and attention
devoted to Pacific defense infrastructure, constructing new air and naval facilities at Midway
Atoll and Wake Island.197
Japan’s surprise attacks on the United States in December 1941 targeted Pearl Harbor as well as
other key regional defense sites, including bases on the Philippines and Wake Island. Allied
prosecution of the ensuing Pacific War relied heavily on both the existing infrastructure and
significant new construction. Military bases, training areas, depots, arsenals, and port facilities
along the West Coast and in Hawaii played important roles in staging and sustaining the
projection of U.S. military forces westward into the Pacific. Dozens of West Coast shipyards—
primarily located in the Puget Sound, Portland, San Francisco Bay, and Los Angeles areas—built
warships and cargo vessels for the U.S. Navy and merchant marine, and Southern California
became one of the country’s major centers of aircraft manufacturing.198 In the Pacific theater
itself, military engineers—particularly naval construction battalions (known as ‘Seabees’)—made
possible operations in remote and austere environments by building dozens of advance bases to
support naval vessels, aircraft, and ground forces.199
By 1945, the United States oversaw a vast infrastructure network spanning from the West Coast
to mainland Asia. In the immediate aftermath of World War II, the U.S. military requisitioned and
built installations in Japan (and its former territories in Korea and Micronesia) to support postwar
occupation and reconstruction activities.200 As tensions with the Soviet Union intensified, U.S.
planners shifted their focus, reorienting America’s regional basing posture around deterring
communist attacks on U.S.-aligned governments, enabling the rapid buildup and supply of forces

195 However, the first engagement between U.S. and German forces occurred in Apra Harbor, Guam, where a German
commerce raider was in port when the United States entered the war. See “History,” Joint Region Marianas/Department
of the Navy, at https://jrm.cnic.navy.mil/About/History/.
196 The newly demonstrated effectiveness of airpower, for instance, led the Army and Navy to build a number of
airfields, while U.S. ratification of the postwar Washington Naval Treaty precluded the construction of new defensive
fortifications in the Pacific until the agreement lapsed in 1936. See Green, By More than Providence, pp. 140-142.
197 Construction of a naval air station and submarine base on Wake Island began in early 1941, while Naval Air Station
Midway Islands was established in August 1941. See “Wake Island,” Naval History and Heritage Command, available
at https://www.history.navy.mil/research/histories/ship-histories/danfs/w/wake-island.html, and Charity Roberts, “The
‘Other’ Battle of Midway,” National Museum of the Pacific War, October 11, 2022 at
https://www.pacificwarmuseum.org/about/news/the-pacific-medals-of-honor-the-other-battle-of-midway-first-
lieutenant-george-h-cannon-u-s-marine-corps.
198 See Arthur Herman, Freedom’s Forge: How American Business Produced Victory in World War II (New York:
Random House, 2012) pp. 130-144 and 176-191 and Jacob Vander Meulen, “West Coast Labor and the Military
Aircraft Industry, 1935-1941” Pacific Northwest Quarterly, Vol. 88, No. 2 (Spring, 1997), available at
https://www.jstor.org/stable/40492294.
199 “The Logistics of Advance Bases,” Naval History and Heritage Command, available at
https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/l/the-logistics-of-advance-
bases.html.
200 In addition to facilities for occupying forces, the military carried out $400 million worth of civilian infrastructure
projects to aid Japan’s postwar reconstruction. See “Military Reconstruction in Japan,” U.S. Army Corps of Engineers,
updated March 2021. Available at https://www.usace.army.mil/About/History/Historical-Vignettes/Military-
Construction-Combat/074-Military-Reconstruction/
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in the event of a crisis, and signaling to both allies and potential adversaries that the United States
was committed to the region.
Beginning with the Truman administration, the geographical anchor of America’s Pacific strategy
was held to be a “defensive perimeter” running from the Aleutians through Japan, the Ryukyu
Islands (Okinawa), and the Philippines.201 The outbreak of the Korean War in 1950 led to the
explicit inclusion of South Korea within this perimeter. The U.S. war effort itself relied heavily
on logistical support from existing and newly developed defense sites—particularly logistical
hubs in Japan.202 By the mid-1950s, DOD’s infrastructure footprint in Northeast Asia had
expanded to encompass dozens of major installations in South Korea, mainland Japan, and
Okinawa.
Elsewhere in the Indo-Pacific, the United States maintained large bases in the Philippines (which
gained independence in 1946, but continued to allow U.S. basing), Guam, and Hawaii. This
basing posture was informed by what became known as the ‘island chain strategy,’ a framework
for containing communist expansion by “mak[ing] safe the offshore island chain which swings
south through Japan, the Ryukyus, the Philippines, Australia and New Zealand” (in addition to
this ‘First Island Chain,’ later strategists would refer to a ‘Second Island Chain’ stretching from
Japan to the Marianas and Palau, as well as a ‘Third Island Chain’ centered on the Hawaiian
Islands). 203
Beginning in the early 1960s, escalating U.S. involvement in the Vietnam War began to place new
and increased demands on Pacific defense sites. By 1969, the United States had built a large
defense infrastructure network in South Vietnam, encompassing 26 “major base camps” spread
throughout the country.204 Installations outside South Vietnam also supported U.S. combat
operations—hundreds of thousands of personnel and millions of tons of materiel passed through
mainland Japan or Okinawa on their way to Vietnam, for instance, while bases in the Philippines
provided logistical support and staging for aircraft and troops.205
With the end of the Vietnam War, the onset of U.S.-Soviet detente, and the opening of relations
between the U.S. and the PRC, the strategic importance of Pacific defense infrastructure appeared
to diminish.206 In the late 1970s, the United States ended its military presence in Taiwan pursuant
to commitments made as part of the normalization of U.S.-PRC ties, and the Carter

201 Dean Acheson, “Remarks by Dean Acheson before the National Press Club,” January 12, 1950. Available at
https://www.trumanlibrary.gov/library/research-files/remarks-dean-acheson-national-press-club.
202 See Terence Gough, U.S. Army Mobilization and Logistics in the Korean War (Washington, D.C.: U.S. Army
Center of Military History, 1987), especially pp. 115-120. Available online at
https://www.govinfo.gov/content/pkg/GOVPUB-D114-PURL-gpo126559/pdf/GOVPUB-D114-PURL-gpo126559.pdf.
203 The ‘island chain strategy’ was first articulated by future Secretary of State John Foster Dulles in the early 1950s.
See John Foster Dulles, “Security in the Pacific,” Foreign Affairs, January 1952, available at
https://www.foreignaffairs.com/articles/united-states/1952-01-01/security-pacific?check_logged_in=1. For later usage,
see, for example, Wilson Vorndick, “China’s Reach has grown; so should the Island Chains,” Center for Strategic and
International Studies, October 22, 2018 at https://amti.csis.org/chinas-reach-grown-island-chains/ and Derek Grossman,
“America is Betting Big on the Second Island Chain,” The Diplomat, September 5, 2020 at
https://thediplomat.com/2020/09/america-is-betting-big-on-the-second-island-chain/.
204 Carroll Dunn, Base Development in South Vietnam, 1965-1970 (Washington, D.C.: Department of the Army, 1991),
p. 135. Available online at https://history.army.mil/html/books/090/90-6/CMH_Pub_90-6.pdf.
205 Thomas Havens, Fire across the Sea: The Vietnam War and Japan 1965-70 (Princeton, NJ: Princeton University
Press, 1987), pp. 84-88, 159.
206 One example of this trend was the adoption in 1969 of the Nixon Doctrine (sometimes called the Guam Doctrine),
which sought to avoid Vietnam-like entanglements by encouraging its allies to handle “problems of military defense”
themselves. See Foreign Relations of the United States, 1969-1976, Volume I, U.S. Department of State at
https://history.state.gov/historicaldocuments/frus1969-76v01/d29.
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administration unsuccessfully sought to withdraw all U.S. ground forces from South Korea.207
Strategic thinking around regional defense infrastructure shifted again in the early 1980s, when
the Reagan administration adopted a global posture that placed more emphasis on regional
forward presence and initiated a major military buildup.208
The end of the Cold War brought another reassessment of the U.S. defense role in the Indo-
Pacific. In its 1990 and 1992 Pacific strategies, DOD outlined a vision of successive regional
force and infrastructure reductions in response to the changed geopolitical environment.209 In
1991, a combination of natural disaster and diplomatic impasse led the U.S. to evacuate its
Philippine bases and end almost a century of military presence in the country. In 1995, however,
the U.S. Security Strategy for the East Asia-Pacific (sometimes referred to as the Nye Report)
avoided further reductions, instead committing the military to “maintain a stable forward
presence in the region, at the existing level of about 100,000 troops, for the foreseeable future.”210
Further adjustments to U.S. basing posture occurred in South Korea, where the U.S. and Republic
of Korea (ROK) governments in 2004 agreed to consolidate U.S. forces in installations centered
on two regional “hub” areas south of Seoul.211
U.S. security strategy in the Indo-Pacific during the 1990s and early 2000s focused on managing
sources of regional instability, especially tensions between North and South Korea and between
the PRC and Taiwan. After the commencement of the Global War on Terror (GWOT) in 2001,
Indo-Pacific locations like Diego Garcia also provided significant logistical support for combat
operations in the greater Middle East, especially following the 2003 invasion of Iraq.212 Defense
infrastructure also supported humanitarian operations in the aftermath of natural disasters,
including the 2004 Indian Ocean tsunami and the 2011 earthquake, tsunami, and nuclear disaster
in Japan.213
Under President Barack Obama, the U.S. military began to shift its focus from GWOT operations
to great power competition with the PRC. In 2011, the Obama administration announced a “pivot

207 In Taiwan, the United States completed the withdrawal of its approximately 10,000 troops by 1979, while President
Carter ultimately withdrew 3,400 of the approximately 40,000 U.S. military personnel who had been stationed in Korea
at the start of his term. See Green, By More Than Providence, p. 353; Jay Mathews, “U.S. Trims Military Forces on
Taiwan,” The Washington Post, November 7, 1978; and Terence Roehrig, “South Korea: An Alliance in Transition,” in
Carnes Lord and Andrew S. Erickson (editors), Rebalancing U.S. Forces: Basing and Forward Presence in the Asia-
Pacific (Annapolis, MD: Naval Institute Press, 2014), pp.70-71.
208 For an assessment of Reagan-era defense spending that includes trends in military construction appropriations, see
Katherine Blakeley, “Defense Spending in a Historical Context: A New Reagan-esque Buildup?” Center for Strategic
and Budgetary Assessments, November 8, 2017, at https://csbaonline.org/reports/defense-spending-in-historical-
context.
209 These included reducing troop levels in Korea and Japan, returning “excess facilities” to host governments, and
obtaining increases to allies’ financial and military contributions to collective security. See “A Strategic Framework for
the Asian Pacific Rim,” Department of Defense, April 1990, pp.7-13.
210 See “United States Security Strategy for the East Asia-Pacific Region,” Department of Defense, February 1995.
Available at https://apps.dtic.mil/sti/pdfs/ADA298441.pdf.
211 The first hub centers on the city of Pyeongtaek and includes Camp Humphreys and Osan Air Base; the second
centers on Daegu and includes USAG-Daegu, Fleet Activities Chinhae, and MCI Camp Mujuk. See Terence Roehrig,
“South Korea: An Alliance in Transition,” in Lord and Erickson (ed.) Rebalancing U.S. Forces, pp.74-75.
212 The U.S. first gained access to Diego Garcia, a British overseas territory, in 1966, and initially used the location as a
communications facility and a base for reconnaissance flights. In the 1980s, the U.S. and U.K. governments
significantly expanded Diego Garcia’s naval and air facilities. See Walter Ladwig, Andrew Erickson, and Justin
Mikolay, “Diego Garcia and American Security in the Indian Ocean,” in Lord and Erickson (ed.) Rebalancing U.S.
Forces, pp. 139-142.
213 See CRS Report R41690, Japan 2011 Earthquake: U.S. Department of Defense (DOD) Response, by Andrew
Feickert and Emma Chanlett-Avery.
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to Asia” to bolster and expand the U.S. role in the region. To that end, DOD shifted more forces
(especially naval) to the Indo-Pacific and negotiated rotational access to additional military bases
in countries like Australia and the Philippines.214 The focus on strategic competition with China
expanded under the Trump administration, which prioritized infrastructure investments in
locations such as Guam and Micronesia while also seeking larger contributions from Indo-Pacific
allies to support U.S. basing costs.215 In 2020, Congress established the Pacific Deterrence
Initiative, a set of regionally focused defense investments that includes infrastructure as a major
activity category (Section 1251 of the William M. (Mac) Thornberry National Defense
Authorization Act for Fiscal Year 2021, P.L. 116-283).

Author Information

Luke A. Nicastro

Analyst in U.S. Defense Infrastructure Policy

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
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under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other
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214 See “FACT SHEET: Advancing the Rebalance to Asia and the Pacific,” White House Office of the Press Secretary,
November 16, 2015. Available at https://obamawhitehouse.archives.gov/the-press-office/2015/11/16/fact-sheet-
advancing-rebalance-asia-and-pacific.
215 “A Free and Open Indo-Pacific,” Department of State, November 4, 2019. Available at https://www.state.gov/wp-
content/uploads/2019/11/Free-and-Open-Indo-Pacific-4Nov2019.pdf
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