Defense Primer: Naval Forces

Updated February 10, 2021
Defense Primer: Naval Forces
“Naval Forces” Refers to Both the Navy
The Navy’s aircraft carriers embark multimission carrier air
and Marine Corps
wings (CVWs) consisting of 60+ aircraft—mostly fixed-
Although the term “naval forces” is often used to refer
wing aircraft, plus a few helicopters. Each CVW typically
specifically to Navy forces, it more properly refers to both
includes 40 or more strike fighters that are capable of air-to-
Navy and Marine Corps forces, because both the Navy and
ground (strike) and air-to-air (fighter) combat operations.
Marine Corps are naval services. For further discussion, see
“Defense Primer: Department of the Navy.” For a
Size of the Navy
discussion of the Marine Corps that focuses on its
The total number of ships in the Navy is a one-dimensional
organization as a ground-combat force, see CRS In Focus
metric that leaves out many other important factors bearing
IF10571, Defense Primer: Organization of U.S. Ground
on naval capability. Notwithstanding this limitation,
Forces, by Barbara Salazar Torreon and Andrew Feickert.
observers often cite the total number of ships in the U.S.
Navy as a convenient way of summarizing the Navy’s
U.S. Strategy and Naval Forces
U.S. naval forces give the United States the ability to
convert the world’s oceans—a global commons that covers
The quoted number of ships in the Navy reflects the battle
more than two-thirds of the planet’s surface—into a
force ships counting method, which is a set of rules for
medium of maneuver and operations for projecting U.S.
which ships count (or do not count) toward the quoted
power ashore and otherwise defending U.S. interests around
number of ships. The battle force ships counting method
the world. The ability to use the world’s oceans in this
was established in the early 1980s and has been modified
manner—and to deny other countries the use of the world’s
by legislation in recent years. Essentially, it includes ships
oceans for taking actions against U.S. interests—constitutes
that are readily deployable overseas, and which contribute
an immense asymmetric advantage for the United States.
to the Navy’s overseas combat capability. The Naval
History and Heritage Command maintains a database on
As discussed elsewhere (see “Defense Primer: Geography,
numbers of ships in the Navy from 1886 to the present. (It
Strategy, and U.S. Force Design), the size and composition
is available here:
of U.S. naval forces reflect the position of the United States
histories/ship-histories/us-ship-force-levels.html.) Since this
as a Western Hemisphere power with a goal of preventing
database extends back to 1886, it uses a different counting
the emergence of regional hegemons in Eurasia. As a result,
method that is more suitable for working with older
the U.S. Navy includes significant numbers of aircraft
historical data. This alternate counting method, however,
carriers, nuclear-powered attack submarines, large surface
produces, for the 1980s onwards, figures for the total size of
combatants, large amphibious ships, and underway
the Navy that are different than the figures produced by the
replenishment ships.
battle force ships counting method. For this reason, using
figures from the NHHC database to quote the size of the
Navy Ship Types
Navy in recent years can cause confusion.
The Navy’s ballistic missile submarines (SSBNs) are
dedicated to performing a singular mission of strategic
Navy Force-Level Goal
nuclear deterrence. The Navy’s other ships, which are
The Navy determines its force-level goal—the size and
sometimes referred to as the Navy’s general-purpose ships,
composition of the fleet it would like to reach and maintain
are generally multimission ships capable of performing a
in coming years—through a Force Structure Analysis
variety of missions other than strategic nuclear deterrence.
(FSA). FSAs are conducted every few years. For each type
The principal types of general-purpose ships in the Navy
of ship, the FSA calculates the number required for
include attack submarines (SSNs); aircraft carriers
warfighting, and the number required for maintaining day-
(CVNs); large surface combatants, meaning cruisers
to-day forward-deployed presence overseas. The Navy’s
(CGs) and destroyers (DDGs); small surface combatants,
current force-level goal, released in December 2016, is to
meaning frigates (FFGs), Littoral Combat Ships (LCSs),
reach and maintain a fleet of 355 battle force ships of
mine warfare (MIW) ships, and patrol craft (PCs);
certain types and numbers.
amphibious ships, whose primary function is to transport
Marines and their equipment and supplies to distant
The Navy and DOD since 2019 have been working to
operating areas and support Marine ship-to-shore
develop a new Navy force-level goal that is expected to
movements and Marine operations ashore; combat logistics
introduce at least some elements of a new fleet architecture
force (CLF) ships, which perform underway replenishment
featuring a smaller proportion of larger ships (such as large-
(UNREP) operations, meaning the at-sea resupply of
deck aircraft carriers, cruisers, destroyers, large amphibious
combat ships; and other support ships of various types.
ships, and large resupply ships); a larger proportion of
smaller ships (such as frigates, corvettes, smaller
amphibious ships, smaller resupply ships, and perhaps

Defense Primer: Naval Forces
smaller aircraft carriers); and a new third tier of large
Forward-Deployed Operations
unmanned surface and underwater vessels. On December 9,
The U.S. Navy is unique among the world’s navies in that,
2020, the outgoing Trump Administration released a
at any given moment, a sizeable fraction of the Navy is
document that presents an envisioned Navy force-level goal
forward-deployed to distant operating areas, particularly the
for achieving by 2045 a Navy with a more distributed fleet
Western Pacific, the Indian Ocean/Persian Gulf region, and
architecture, including 382 to 446 manned ships and 143 to
the waters around Europe. At any given moment, roughly
242 large unmanned vessels. The Biden Administration can
30% or more of the Navy, including two or three CSGs and
choose to adopt, revise, or set aside this document.
two or three ARGs, might be forward-deployed. Having
enough ships to maintain these forward deployments is a
Actual Size of the Navy
major influence on calculations that determine the Navy’s
The size of the Navy in recent years has generally ranged
force-level goal.
between 270 and 300 battle force ships. As of February 10,
2021, the figure was 297.
The forward-deployed presence of Navy ships is intended
to support a number of ongoing or potential missions,
Nuclear-Powered Ships
including deterrence of potential aggressors; reassurance of
The Navy’s submarines and aircraft carriers are all nuclear
allies and partners; engagement operations with foreign
powered, meaning that they use on-board nuclear reactors
naval and other military forces (which can strengthen
to generate power for propulsion and for running shipboard
political bonds and improve interoperability between the
equipment. Navy submarines each have one reactor; Navy
Navy and those other forces); intelligence, surveillance, and
aircraft carriers each have two. All other Navy ships are
reconnaissance (ISR) operations; rapid response in
conventionally powered, meaning that they burn petroleum-
humanitarian assistance/disaster response (HA/DR)
based fuels for propulsion and shipboard power.
situations; non-combatant evacuation operations (NEOs);
counter-terrorist operations, crisis response and
Navy Nuclear Weapons
containment, and timely initial actions during the early (and
The Navy maintains a neither-confirm-nor-deny (NCND)
potentially critical) stages of a conflict.
policy regarding the presence or absence of nuclear
weapons on specific ships. In general, however, it is
Forward-Homeported Ships
understood that the only Navy ships that carry nuclear
Most of the Navy’s ships are homeported in the United
weapons are SSBNs, which carry nuclear-armed
States. To help support its ability to maintain its forward-
submarine-launched ballistic missiles (SLBMs). All of the
deployed presence, some Navy ships are homeported in
Navy’s other nuclear weapons, which were referred to
forward locations. The Navy’s largest forward-homeporting
collectively as non-strategic naval nuclear weapons, were
location is Japan, where a CSG, an ARG, and some mine
withdrawn from the fleet as part of a unilateral initiative
warfare ships are homeported. Additional Navy ships are
announced by President George H.W. Bush at the end of
forward-homeported elsewhere in the Pacific, in the Persian
the Cold War in 1991.
Gulf (at Bahrain), and in or near the Mediterranean (in
Spain and Italy).
Navy Formations
Naval forces are modular and scalable—Navy ships can be
Relevant Statutes
combined into formations of various types and sizes that are
tailored for their intended missions. The two most
Title 10, U.S. Code, Subtitle C – Navy and Marine Corps
prominent types of naval formations are carrier strike
groups (CSGs)
and amphibious ready groups (ARGs).

The composition of a CSG can vary, but typically includes
a CVN with its embarked CVW, perhaps three to five
CRS Products
surface combatants (typically one cruiser, plus some
CRS Report RL32665, Navy Force Structure and Shipbuilding
destroyers), a CLF ship, and perhaps an SSN. An ARG
Plans: Background and Issues for Congress, by Ronald O'Rourke
typically includes three amphibious ships—one LHA/LHD
type “big deck” amphibious assault ship (which resembles a

medium-sized aircraft carrier) and two smaller (but still
Other Resources
sizeable) amphibious ships known as LPDs and LSDs. An
ARG typically embarks a Marine Expeditionary Unit
Congressional Budget Office, The U.S. Military’s Force Structure:
(MEU), which includes more than 2,000 Marines and their
A Primer, July 2016, particularly Chapter 3 (pp. 45-79)
equipment (including some aircraft) and supplies. A third
Department of the Navy, Highlights of the Department of the
type of naval formation is a Surface Action Group (SAG),
Navy FY 2021 Budget, accessed March 17, 2020, at
which consists of a few or several surface combatants,
without an aircraft carrier. Navy ships sometimes operate
by themselves—all SSBNs and many SSNs operate this
U.S. Navy Program Guide 2017, accessed August 12, 2020, at
way, as do some surface combatants and amphibious ships
that are deployed to lower-threat areas (such as South
1/1/NPG17.PDF. (The 2017 edition of this program guide is
America or parts of Africa) for purposes of engaging with
the most recent edition available.)
allied or partner forces in those areas.

Defense Primer: Naval Forces

Ronald O'Rourke, Specialist in Naval Affairs

This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
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