Updated December 3, 2019
National Park Service Affiliated Areas: An Overview
In addition to managing the 419 units of the National Park
System, the National Park Service (NPS) manages or assists
other areas that are linked in importance and purpose to the
larger system. These related areas may be recognized by
Congress and may receive assistance from NPS but are
typically owned and administered primarily by nonfederal
entities. Among these related areas are 25 sites that NPS
has classified under the title of affiliated areas. NPS defines
affiliated areas as locations that “preserve significant
properties outside the National Park System ... [and that]
draw on technical or financial aid from the National Park
Service” (National Parks: Index 2012-2016, p. 118).
History of Affiliated Status
The standard by which NPS defines and categorizes
“affiliated areas” has evolved and changed over the years.
At times, Congress has attempted to clarify which areas fall
within this status. In 1970, Congress passed legislation that
defined units of the National Park System as “any area of
land and water now or hereafter administered by the
Secretary of the Interior through the National Park Service
for park, monument, historic, parkway, recreational or other
purposes” (P.L. 91-383). The 1970 law specifically
excludes from this definition “miscellaneous areas
administered in connection therewith,” that is, properties
and sites that are neither federally owned nor directly
administered by the NPS but that receive some federal
assistance. In 1975, NPS issued the National Parks: Index
(an occasional publication from NPS that serves as the
official list of National Park System areas), in which the
agency classified nine units for the first time under the new
title of affiliated areas.
Despite this new definition, affiliated status continued to
shift in the years following 1970. At times, the status
included designations such as national heritage areas, rivers
in the National Wild and Scenic Rivers System, and trails in
the National Trails System, while at other points NPS
excluded these areas from the affiliated categorization. In
1988, Congress passed legislation directing NPS to define
the “criteria for the elements of national significance and
other factors necessary for a proposed area to be considered
appropriate for inclusion as an affiliated area” (P.L. 100336). Later that year, NPS issued proposed regulations that
included a revised definition and set criteria for affiliated
area designation (53 Federal Register 32115). While these
regulations were not finalized, they are reflected in the
current standards for inclusion outlined in NPS’s
Management Policies 2006 (see “Designation Criteria”).
In 1989, NPS issued a memorandum entitled “Classification
of NPS Units and Related Areas” that outlined some
difficulties in classifying areas where NPS does not directly
administer the area but has some special cooperative
arrangement. “Many of these arrangements defy simple
formulas for defining what we administer,” the memo
stated. A 1990 NPS report to Congress—delivered in
compliance with P.L. 100-336—reaffirmed this finding,
stating that, “Areas have been classified as affiliated
because they did not fit the definition of a park system unit
rather than because they did meet some clearly defined
criteria.” In response, the report recommended that
Congress recognize the affiliated area category and endorse
the criteria proposed by NPS for affiliated area status.
The criteria recommended in the 1990 NPS report are
largely reflected in the NPS Management Policies 2006
(Section 1.3.4), which establishes eligibility guidelines for
affiliated area status. To be eligible, proposed areas must
Meet the same standards for significance and suitability
that apply to units of the National Park System;
Require some special recognition or technical assistance
beyond what is available through existing NPS
Be managed in accordance with the policies and
standards that apply to units of the system; and
Be assured of sustained resource protection, as
documented in a formal agreement between the service
and the nonfederal management entity.
Designation Process and Authority
The 25 existing affiliated areas were primarily established
legislatively, although some were established through
administrative action by the Secretary of the Interior under
the authority of the Historic Sites Act of 1935 (54 U.S.C.
§§320101 et seq.). Under the act, as amended, an
administratively designated site may not receive federal
funding unless Congress specifically appropriates funding
for that site.
Although many of the sites were established in statute, in
most cases the establishing laws did not identify them or
title them as affiliated areas. Instead, the sites were
designated with varying titles; they include 9 national
historic sites and 4 national memorials, as well as 12 sites
with other, often unique, titles.
The oldest existing affiliated area is the Jamestown
National Historic Site. The site was designated on
December 18, 1940, by administrative action in which the
Secretary of the Interior called for “a unified program of
development and administration” between NPS and the
Association for the Preservation of Virginia Antiquities
National Park Service Affiliated Areas: An Overview
(APVA). The APVA continues to own and operate this site.
The most recent site established as an affiliated area is the
Parker’s Crossroads Battlefield in 2019, which Congress
designated in the John D. Dingell, Jr. Conservation,
Management, and Recreation Act (P.L. 116-9).
warrant further study through a full special resource study.
Recently, some Members have requested that NPS conduct
certain reconnaissance surveys with the specific intention of
determining whether a given site would be appropriate for
Table 1. Examples of NPS Affiliated Areas
Some sites previously designated or categorized as an
affiliated area have been removed from this classification.
Sometimes, this removal was the result of a shift in how
NPS defines and lists affiliated areas, as was the case with
several national heritage areas and early units of the
National Trails System. Other times, sites previously
categorized as affiliated areas were redesignated as full
units of the National Park System. For example, in 2009,
Congress redesignated Port Chicago Naval Magazine
National Memorial as a unit of the National Park System
(P.L. 111-84). More recently, in 2016, President Obama
proclaimed the Belmont-Paul Women’s Equality National
Monument as a unit of the System (81 Federal Register
22503), more than 40 years after Congress had designated
the site as a national historic site (P.L. 93-487).
P.L. 92-551, 86 Stat. 1164,
October 25, 1972
Natural Bridge State
Sec. Decision Memo of
August 29, 2016
Ice Age National
P.L. 88-655, 78 Stat. 1087,
October 13, 1964
P.L. 104-333, 110 Stat.
4162, November 12, 1996c
Source: CRS. For a nearly complete list of NPS affiliated areas as of
2016, see The National Parks: Index 2012-2016. Since publication of
the Index, two additional affiliated areas have been established
(Parker’s Crossroads Battlefield and Natural Bridge State Park).
a. International Peace Garden is recognized as a National Park
System affiliated area by virtue of federal funding authorized in
the Acts of October 25, 1949; June 28, 1954; August 28, 1958;
and October 26, 1974. Although the site was not officially
designated as an affiliated area in legislation, NPS has categorized
it as such since the first listing of affiliated areas in 1975.
b. Portions of the International Peace Garden site are located in
the Canadian province of Manitoba.
c. The enabling legislation for the New Bedford Whaling National
Historical Park (P.L. 104-333) also established the Inupiat
Heritage Center (previously known as North Slope Borough
Cultural Center) as a “related facility” of the site. NPS
subsequently categorized the site on its own as an affiliated area.
At times, Congress may designate affiliated areas following
the completion of a special resource study by NPS.
Typically, this may occur when Congress directs NPS to
conduct a study to determine whether a given site is an
appropriate candidate for inclusion as a unit of the National
Park System. According to P.L. 105-391, a special resource
study will determine whether an area under study (1)
possesses nationally significant natural or cultural resources
and (2) is a suitable and feasible addition to the system. If
the study determines that a site meets the criteria for
national significance but is not suitable or feasible for NPS
management as a unit of the park system, NPS may
recommend the site for affiliated status. Recent legislation
would direct NPS to conduct special resource studies
specifically aimed at determining the feasibility of a site for
affiliated status (see “Legislation”).
Affiliated site designation also may arise from less formal,
preliminary studies conducted by NPS at the request of
Members of Congress. Similar to special resource studies,
these reconnaissance surveys typically are used to
determine whether a given site would meet the criteria for
addition to the National Park System and, if so, would
The only site previously designated as a unit of the National
Park System to be redesignated as an affiliated area is the
Oklahoma City National Memorial. Congress initially
authorized the site as a full unit of the park system (albeit
one administered in partnership with a private entity) in
1997 (P.L. 105-58). Congress redesignated the site as an
affiliated area in 2004 (P.L. 108-199).
Administration, Funding, and Ownership
NPS is generally less involved in the funding and
management of affiliated areas than of park system units.
Typically, NPS directly administers units of the park
system, whereas it provides technical and financial
assistance to related areas, which are administered primarily
by nonfederal entities. The degree to which NPS has a role
in the management or administration of an affiliated area
typically is defined in the enabling legislation for the site or
through the development of a general management plan.
Federal funding for affiliated areas varies on a site-by-site
basis. Congress has authorized federal funding for some
affiliated areas in enabling legislation or through the annual
appropriations process. Other sites receive no federal
funding but receive technical assistance from NPS.
The majority of affiliated areas are nonfederally owned.
However, NPS does own portions of several listed areas,
including more than 90,000 acres of the Pinelands National
Reserve, the largest affiliated area by size.
Legislation in the 116th Congress
In the 116th Congress, P.L. 116-9 established Parker’s
Crossroads Battlefield as an affiliated area, designating the
City of Parker’s Crossroads and the Tennessee Historical
Commission as joint management entities for the site. H.R.
486 would direct the Secretary to conduct a special resource
study to evaluate designating Chicano Park and its murals
in San Diego, CA, as an affiliated area.
Mark K. DeSantis, Analyst in Natural Resources Policy
National Park Service Affiliated Areas: An Overview
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