In 1964, the Wilderness Act established a national system of congressionally designated areas to be preserved in a wilderness condition: "where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain."¹ The National Wilderness Preservation System (NWPS) was originally created with approximately 9.1 million acres designated in national forest system lands managed by the Forest Service. Congress has since added more than 100 million acres to the NWPS (see Table 1). Wilderness areas have been designated on land managed by each of the four federal land management agencies—the Forest Service (FS) in the Department of Agriculture, and the National Park Service (NPS), Fish and Wildlife Service (FWS), and Bureau of Land Management (BLM) in the Department of the Interior.² Federal agencies, Members of Congress, and interest groups have recommended additional lands for inclusion in the NWPS. Furthermore, at the direction of Congress, agencies have studied, or are studying, the potential of their lands for wilderness designation. This report provides a brief history of wilderness, describes what wilderness is, identifies permitted and prohibited uses in wilderness areas, and provides data on the 111.7 million acres of designated wilderness areas as of July 6, 2022. For information on wilderness legislation, see CRS Report R41610, Wilderness: Issues and Legislation.

History of Wilderness

As the United States was formed, the federal government acquired 1.8 billion acres of land through purchases, treaties, and other agreements. Initial federal policy was generally to transfer land to states and private ownership, but Congress also provided for reserving certain lands for federal purposes. Over time, Congress has reserved or withdrawn increasing acreage for national parks, national forests, wildlife refuges, etc. The general policy of land disposal was formally changed to a policy of retaining the remaining lands in the Federal Land Policy and Management Act of 1976 (FLPMA).³

The early national forests were envisioned as working forests managed for multiple purposes.⁴ In time, some FS leaders recognized the need to preserve some areas in a natural state. Acting at its own discretion, and at the behest of conservationist and then-employee Aldo Leopold, the FS administratively designated the first wilderness area in the Gila National Forest in New Mexico in 1924. In the succeeding decades, the agency's system of administratively designated wilderness, wild, and primitive areas grew to 14.6 million acres. However, in the 1950s, increasing timber harvests and recreational use of the national forests led to public concerns about the permanence of this system, as there was no law to prevent a future change to those administrative designations.

In response, the 88^th Congress enacted the Wilderness Act in 1964. The act described the attributes and characteristics of wilderness, and it prohibited or restricted certain activities in wilderness areas to preserve and protect the designated areas, while permitting other activities to occur. The act reserves to Congress the authority to designate areas as part of the NWPS.

The NWPS began with the approximately 9.1 million acres of national forest lands that had been identified administratively as wilderness or wild areas. The Wilderness Act directed the Secretary of Agriculture to review the agency's nearly 5.5 million acres of primitive areas, and the Secretary of the Interior to evaluate the wilderness potential of National Park System and National Wildlife Refuge System lands. The Secretaries were to report their recommendations to the President and to Congress within 10 years (i.e., by 1974). Separate recommendations were made for each studied area, and many areas recommended for wilderness were later designated, although some of the recommendations are still pending. In 1976, FLPMA directed the Secretary of the Interior to conduct a similar review of the public lands administered by BLM within 15 years (i.e., by 1991). BLM submitted its recommendations to the President, and presidential recommendations were submitted to Congress (see "BLM Wilderness Review and Wilderness Study Areas").

The 90^th Congress began expanding the Wilderness System in 1968, as shown in Table 1. Five laws were enacted, creating five new wilderness areas encompassing 792,750 acres in total. Wilderness designations generally increased in each succeeding Congress, rising to a peak of about 60.8 million acres designated during the 96^th Congress (1979-1980), the largest amount designated by any Congress. This figure included the largest single designation of 56.4 million acres of wilderness through the Alaska National Interest Lands Conservation Act.⁵ The 98^th Congress enacted more wilderness laws (21) and designated more acres (8.5 million acres in 21 states) outside of Alaska than any Congress since the NWPS was created.

Including the Wilderness Act, Congress has enacted more than 120 laws designating new wilderness areas or adding to existing ones, as shown in Table 1. The NWPS now contains 803 wilderness areas managed by the four federal land management agencies, with approximately 111.7 million acres in 44 states and Puerto Rico, as shown in Table 2.⁶ The agencies have recommended that additional lands be added to the Wilderness System; these lands are generally managed to protect their wilderness character while Congress considers adding them to the Wilderness System (see "Wilderness Review, Study, and Release"). The agencies are studying additional lands to determine if these lands should be added to the NWPS. However, comprehensive data on the lands recommended and under review for wilderness potential are not publicly available.

What Is Wilderness?

The Wilderness Act described wilderness as an area of generally undisturbed federal land. Specifically, Section 2(c) defined wilderness as

A wilderness, in contrast with those areas where man and his works dominate the landscape, is hereby recognized as an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain. An area of wilderness is further defined to mean ... an area of undeveloped Federal land retaining its primeval character and influence, without permanent improvements or human habitation, which is protected and managed so as to preserve its natural conditions and which (1) generally appears to have been affected primarily by the forces of nature, with the imprint of man's work substantially unnoticeable; (2) has outstanding opportunities for solitude or a primitive and unconfined type of recreation; (3) has at least five thousand acres of land or is of sufficient size as to make practicable its preservation and use in an unimpaired condition; and (4) may also contain ecological, geological, or other features of scientific, educational, scenic, or historical value.⁷

This definition provides some general guidelines for determining which areas should or should not be designated wilderness, but the law contains no specific criteria. Even the numerical standard (5,000 acres) is not absolute; smaller areas can be designated.

These imprecise criteria stem in part from differing perceptions of what constitutes wilderness. To some, wilderness is an area where there is absolutely no sign of human presence: no traffic can be heard (including aircraft); no roads, structures, or litter can be seen. To others, sleeping in a busy campground with electricity, running water, and play areas is a wilderness experience. Complicating these differing perceptions is the wide range of ability to "get away from it all" in various settings. In open terrain, human developments may be visible for miles, whereas a dense forest may obscure developments that are just yards away.

In an attempt to accommodate contrasting views of wilderness, the Wilderness Act provided certain exemptions and delayed implementation of restrictions for wilderness areas, as discussed below. At times, Congress has also responded to the conflicting demands of various interest groups by allowing additional exemptions for certain uses (especially for existing activities) in particular wilderness designations. The subsequent wilderness statutes have not designated wilderness areas by amending the Wilderness Act. Instead, they are independent statutes. Although nearly all of these statutes direct management in accordance with the Wilderness Act, many also provide unique management guidance for their designated areas. Ultimately, wilderness areas are whatever Congress designates as wilderness, regardless of developments or activities that some might argue conflict with the act's definition of wilderness.

Management Provisions in the Wilderness Act

Several separate sections of the Wilderness Act specify general principles for managing wilderness. Congress specified that wilderness lands were to be "administered for the use and enjoyment of the American people in such manner as will leave them unimpaired for future use and enjoyment as wilderness, and so as to provide for the protection of these areas, the preservation of their wilderness character, and for the gathering and dissemination of information regarding their use and enjoyment as wilderness."⁸ Congress reiterated in a separate section that administering agencies were responsible for preserving "wilderness character."⁹ Congress also specified that wilderness was to be managed to preserve its natural conditions.¹⁰

Because it is mentioned twice in the Wilderness Act, "wilderness character" is often viewed as central to wilderness management; all four federal land management agencies' policies specify an objective of managing wilderness to preserve its wilderness character.¹¹ However, the term is not defined in the act. Some of the agencies have interpreted "wilderness character" to be related to the characteristics described in Section 2(c) of the act (see "What Is Wilderness?"), and have elaborated on words from this section, such as untrammeled, natural, undeveloped, and/or primitive and unconfined recreation, in defining their wilderness management policies.¹² Others have defined wilderness character in other ways.¹³ The agencies also specify other management objectives, such as promoting certain conditions of the natural environment or managing wilderness for certain public purposes.¹⁴

In addition to these general management principles, the Wilderness Act specifically addressed a number of prohibited and permitted uses of wilderness, discussed below.

Prohibited Uses

The Wilderness Act generally prohibits various activities in designated wilderness areas. In some cases, Congress specified exceptions to some of these prohibitions, which are listed under each heading. Congress also specified general exceptions, which are described under "Exceptions to Prohibited Uses."

Commercial Enterprise

The Wilderness Act prohibits "commercial enterprise," generally interpreted to mean most business activities conducted for profit, including commercial resource development such as timber harvesting. This provision excludes "activities which are proper for realizing the recreational or other wilderness purposes of the areas."¹⁵ Congress also made exceptions for some specific commercial activities, such as grazing (see "Permitted Uses").

Motorized and Mechanized Equipment or Vehicles

The Wilderness Act prohibits use of "motor vehicles," "motorized equipment or motorboats," "landing of aircraft," and "mechanical transport." In total, these prohibitions are generally construed to prohibit the use of equipment or transportation that is not human-powered (e.g., cars, trucks, off-highway vehicles, chain saws, and bulldozers) and human-powered, mechanized vehicles (e.g., bicycles, strollers). Aircraft or motorboats (but not other motorized or mechanized use) may continue to be used in wildernesses where their use was established prior to designation, subject to any restrictions the Secretary of Agriculture imposes.

Structures, Installations, and Roads

The Wilderness Act specifies that there shall be "no structure or installation" within designated wilderness areas. "Structures or installations" are generally interpreted to mean human constructions, such as buildings, pipelines, communications towers, scientific instruments, fences, and others. The Wilderness Act also generally prohibits permanent or temporary roads in wilderness areas. The Wilderness Act is silent on the treatment of any infrastructure in place at the time of the designation. Within certain national forest wilderness areas, the President may authorize the establishment and maintenance of certain water resources installations (such as reservoirs, power projects, and transmission lines) and may authorize associated road construction and maintenance essential to those developments.¹⁶

Exceptions to Prohibited Uses

The Wilderness Act provides several general exceptions to some prohibited uses. Commercial enterprise and permanent roads are not subject to these exceptions (i.e., are never allowed, except as described above). For the other prohibited uses, these exceptions are

• When uses are subject to existing private rights
• Measures required in emergencies involving health and safety risks to people
• Measures necessary to control fire, insects, and diseases¹⁷
• To meet "minimum requirements for the administration of the area"¹⁸

The agencies have established procedures for evaluating uses of these exceptions (see text box on "Minimum Requirements Analysis").

Permitted Uses

The Wilderness Act, and subsequent statutes, authorized some uses to continue, particularly if the uses were authorized at the time of designation. For example, the Wilderness Act specifically directs that "the grazing of livestock, where established prior to the effective date of this Act, shall be permitted to continue subject to such reasonable regulations as are deemed necessary by the Secretary of Agriculture."¹⁹ Congress provided additional guidance on continuing livestock grazing at historic levels in designated wilderness areas through committee reports.²⁰

The Wilderness Act extended the mining and mineral leasing laws for wilderness areas in national forests for 20 years, through 1983. Until midnight on December 31, 1983, new mining claims and mineral leases were permitted for those wilderness areas and exploration and development were authorized subject to any access regulations prescribed by the Secretary of Agriculture.²¹ On January 1, 1984, the Wilderness Act withdrew the specified national forest wilderness areas from all forms of appropriation under the mining laws.

Although not specifically permitted or prohibited in the Wilderness Act, "primitive and unconfined" recreation is described as a characteristic of wilderness (see "What Is Wilderness?" "What is Wilderness?"). Therefore, recreation is generally considered a permitted use of wilderness, although specific activities may be prohibited. For example, hiking, camping, canoeing, and horseback riding are generally considered to be allowed, whereas off-highway vehicle use and mountain biking are generally prohibited in accordance with the act's prohibitions on motorized and mechanized transport. Other recreational uses may require case-by-case analysis: for example, agencies may need to determine whether commercial guiding or outfitting is "necessary" for realizing the recreational purposes of wilderness.²² Provisions of law may address recreational use of individual wildernesses (see "Management Provisions in Individual Wilderness Laws"). Whether individual wildernesses are used for recreational purposes (and which purposes) may depend on a number of factors, such as terrain and climate, ease of access, distance from population centers, and others.

Other Management Provisions

Other management issues addressed in the Wilderness Act relate to jurisdictional concerns or private rights:

• State Fish and Wildlife Jurisdiction and Responsibilities. The Wilderness Act explicitly directs that wilderness designations have no effect on state jurisdiction or responsibility over fish and wildlife.²³
• Water Rights. The Wilderness Act does not claim or deny a reserved water right.²⁴
• Land and Rights Acquisition and Future Designations. The Wilderness Act authorizes the acquisition of inholdings, including through donation or exchange for other federal land, subject to appropriations. ²⁵

Relation to Management of Underlying Federal Land

Units of the NWPS are designated as part of and within existing units of federal land—for example, a wilderness within a national forest remains part of the National Forest Service (NFS) and is managed by the FS. Furthermore, the Wilderness Act specifies that its purposes are "within and supplemental to" the purposes for which units of the NFS, NWRS, and National Park System are established and administered.²⁶ In general, this means the management provisions applicable to those units of federal land apply, particularly those governing management direction and restricting activities. For example, hunting is not generally allowed in the National Park System but is generally allowed on most NFS and BLM lands. Thus, hunting may be prohibited in National Park System wilderness but may be authorized in NFS or BLM wilderness.

Management Provisions in Individual Wilderness Laws

Congress designates wilderness through individual wilderness laws, which generally specify management of the designated area in accordance with the Wilderness Act. However, many wilderness laws have allowed various nonconforming uses and conditions in the designated wilderness, especially if such uses were in place at the time of designation. Wilderness laws also consider situations that were not directly contemplated in the act. Some provisions that have been included in wilderness laws are described below.

• Structures and Installations. Although they are prohibited under the Wilderness Act, some subsequent wilderness statutes have addressed structures and installations in varying ways. Some have authorized continued maintenance of existing structures or installations. Others have authorized certain kinds of structures or installations, such as research instruments.²⁷
• Motorized Access. Some statutes have explicitly allowed motorized access for state agencies for fish and wildlife management activities. Several statutes have expressly permitted low-level military overflights of wilderness areas, although the Wilderness Act does not prohibit overflights.²⁸
• Energy and Minerals. Some wilderness laws have directed continued energy or mineral development and extraction or otherwise allowed use of an existing mine or well to continue within designated areas. Other wilderness laws have specifically withdrawn the designated areas from availability under energy, mineral, or geothermal laws, though valid existing rights are not terminated and can be developed under reasonable regulations.²⁹
• Public Access. Many wilderness statutes have authorized closing certain wilderness areas (or parts thereof) to public access. Wilderness statutes also have allowed access for other specific activities, such as access to cemeteries within designated areas or for tribal activities.³⁰
• Buffer Zones. The Wilderness Act is silent on the issue of buffer zones around wilderness areas as a means to protect the designated areas. However, in response to concern that designating wilderness areas would restrict management of adjoining federal lands, language in many subsequent wilderness statutes has prohibited buffer zones that would limit uses and activities on federal lands around the wilderness areas.³¹
• Jurisdiction and Authorities of Other Federal Agencies. Several wilderness statutes have directed that other agencies' specific authorities, jurisdiction, and related activities be allowed to continue. For example, some wilderness statutes specify that the wilderness designation has no effect on law enforcement, generally, or on U.S.-Mexico border relations, drug interdiction, or military training.³²
• Water Rights. Wilderness statutes have provided different directions concerning federal reserved water rights associated with the designated wilderness areas. Some wilderness statutes have expressly reserved, or denied, claims to federal water rights.³³

Individual wilderness laws sometimes reiterate provisions from the Wilderness Act. For example, many wilderness statutes expressly direct continued livestock grazing in conformance with the Wilderness Act and the committee reports. Others reiterate state involvement with fish and wildlife, sometimes referring only to state jurisdiction (not responsibilities). Wilderness statutes frequently provide that state law dictates regulation of water allocation and use.

Wilderness Review, Study, and Release

Congress directed the four land-management agencies to review the wilderness potential of their lands and make recommendations regarding the lands' suitability for wilderness designation. Congress acted on many of those recommendations by either designating lands as wilderness or by releasing lands from further wilderness consideration. However, some recommendations remain pending. Questions and discussions persist over the protection and management of these areas, which some believe should be designated as wilderness and others believe should be available for development. This debate has been particularly controversial for FS inventoried roadless areas and BLM wilderness study areas.³⁴

Forest Service Wilderness Reviews and Inventoried Roadless Areas³⁵

The Wilderness Act directed the Secretary of Agriculture to review the FS primitive areas—certain administratively designated NFS lands where development was limited—for wilderness potential. The act directed the FS to make recommendations to the President regarding the suitability of those lands for wilderness designation. The FS attempted to inventory and study so-called roadless areas—primitive areas and other undeveloped areas identified by the FS—for wilderness potential in two separate reviews, known as Roadless Area Review and Evaluation (RARE) I and II. However, legal action blocked the results of both reviews and limited FS management of lands studied in the reviews, including those not recommended for wilderness designation. Congress intervened to legislatively address the reviewed areas, such as by designating them as wilderness or expressing that the FS obligation to review the lands was fulfilled (known as release language).

In 2001, the Clinton Administration addressed the management and protection of NFS inventoried roadless areas (IRAs, primarily RARE II areas not designated as wilderness). The Administration developed regulations that would prohibit most road construction, reconstruction, and timber harvesting in IRAs (the 2001 Rule).³⁶ More than a decade of litigation followed, shaped by the issuance of a contrasting rule by the George W. Bush Administration in 2005 and ongoing legal challenges to those rules. At certain points, federal courts were in conflict, leading to uncertainty over which rule (if any) was in effect. However, after resolution of the legal challenges to the nationwide rules, the 2001 Rule returned to effect in most areas of the United States. Due to related rulemaking efforts, additional roadless rules are in effect for the remaining areas, including individual rules for the states of Colorado and Idaho. In 2020, the FS exempted the Tongass National Forest in Alaska from the 2001 Rule, eliminating approximately 9.3 million acres of IRAs.³⁷

BLM Wilderness Review and Wilderness Study Areas

Congress directed BLM to consider wilderness as a use of its public lands in the 1976 enactment of FLPMA. Section 603 of FLPMA required BLM to make an inventory of roadless areas greater than 5,000 acres and to recommend the suitability for designation of those areas to the President within 15 years of October 21, 1976.The President then had two years to submit wilderness recommendations to Congress. BLM presented its recommendations by October 21, 1991, and Presidents George H. W. Bush and Bill Clinton submitted wilderness recommendations to Congress. Although BLM has reviewed these areas and Congress has enacted several statutes designating BLM wilderness areas, many of the wilderness recommendations for BLM lands remain pending. As of September 2020, there are approximately 11.6 million acres of BLM wilderness study areas.³⁸

There are two continuing issues for potential BLM wilderness: BLM's management requirements of the wilderness study areas under FLPMA, and whether BLM has a continuing obligation under FLPMA to conduct wilderness reviews.

Protection of BLM Wilderness Study Areas

Section 603(c) of FLPMA directs the agency to manage Wilderness Study Areas (WSAs) designated under its provisions "until Congress has determined otherwise … in a manner so as not to impair the suitability of such areas for preservation as wilderness."³⁹ Thus, BLM must protect the WSAs as if they were wilderness until Congress enacts legislation that releases BLM from that responsibility. This responsibility is sometimes referred to as a non-impairment obligation or standard.

WSAs have been subject to litigation challenging BLM's protection. In the early 2000s, BLM was sued for not adequately preventing impairment of WSAs from increased off-road vehicle use. In Norton v. Southern Utah Wilderness Alliance, the U.S. Supreme Court ruled that the non-impairment obligation was not enforceable by court challenge.⁴⁰ The Court held that although WSA protection was mandatory, it was a broad programmatic duty of BLM and not a discrete agency obligation. The Court also concluded that the relevant FLPMA land use plans (which indicated that WSAs would be monitored) constituted only management goals that might be modified by agency priorities and available funding, and were not a basis for enforcement under the Administrative Procedure Act. Therefore, it appears that although BLM actions that would impair the suitability of WSAs as wilderness could be enjoined, as with any agency enforcement obligation,⁴¹ forcing BLM to take protective action would be difficult at best.

BLM Reviews for Wilderness Potential

Despite BLM's continuing obligation under FLPMA Section 201 to identify the resources on its lands, giving priority to areas of critical environmental concern,⁴² it is unclear whether BLM is required to review its lands specifically for wilderness potential after expiration of the reviews required by Section 603 of FLPMA.⁴³ In contrast to the FS, which must revise its land and resource management plans at least every 15 years, BLM is not required to revise its plans on a specified cycle; rather, it must revise its land and resource management plans "when appropriate." Furthermore, while NFMA includes wilderness in the planning process, both directly and by reference to the Multiple Use-Sustained Yield Act of 1960, FLPMA is silent on wilderness in the definitions of multiple use and sustained yield and in the guidance for the BLM planning process. Thus, if and when BLM conducts future wilderness reviews are less certain than if and when the FS conducts future wilderness reviews.

DOI Wilderness Policy Changes

With each Administration, DOI has changed its policy regarding how it administers areas with wilderness potential. In September 2003, then-DOI Secretary Gale Norton settled litigation challenging a 1996 policy identifying large amounts of wilderness-suitable lands.⁴⁴ Following the settlement, the BLM assistant director issued guidance (known as Instruction Memorandum 2003-274) prohibiting further reviews and limiting the term wilderness study areas and the non-impairment standard to areas already designated for the original FLPMA Section 603 reviews of the 1970s and 1980s.⁴⁵ The guidance advised, in part, that because the FLPMA Section 603 authority expired, "there is no general legal authority for the BLM to designate lands as WSAs for management pursuant to the non-impairment standard prescribed by Congress for Section 603 WSAs."⁴⁶

On December 22, 2010, then-DOI Secretary Ken Salazar issued Order No. 3310, known as the Wild Lands Policy, addressing how BLM would manage wilderness.⁴⁷ This order indirectly modified the 2003 wilderness guidance without actually overturning the direction (or even acknowledging it). The order relied on the authority in FLPMA Section 201 to inventory lands with wilderness characteristics that are "outside of the areas designated as Wilderness Study Areas and that are pending before Congress" and designated these lands as "Wild Lands." It also directed BLM to consider the wilderness characteristics in land use plans and project decisions, "avoiding impairment of such wilderness characteristics" unless alternative management is deemed appropriate. Whereas Instruction Memorandum 2003-274 indicated that, except for extant FLPMA Section 603 WSAs, the non-impairment standard did not apply, Order No. 3310 appeared to require an affirmative decision that impairment is appropriate in a FLPMA Section 201 wilderness resource area. Otherwise, under Order No. 3310, impairment must be avoided. After Congress withheld funding, then-Secretary Salazar revoked the order in June 2011 and stated that BLM would not designate any wild lands.⁴⁸ Despite the order being formally revoked, Congress has continued to withhold funding in annual appropriations acts.⁴⁹

Potential Wilderness Designated by Congress

Congress has enacted a number of wilderness statutes designating potential wilderness areas. Potential wilderness areas are to become wilderness when certain conditions are met, as specified in the designating statute. For example, some statutes have specified that the potential wilderness will be designated as wilderness on the date the relevant Secretary publishes notice in the Federal Register specifying that nonconforming uses of the area (often, uses prohibited in the Wilderness Act) have ceased. Such statutes may specify that the potential wilderness areas are to be managed as wilderness, notwithstanding certain prohibited uses, until such time. Other statutes may specify that the wilderness designation is dependent upon other factors (e.g., land acquisition) or at other times (e.g., after a certain number of years have passed).

Data on Wilderness Designations

The wilderness data presented in Table 2 are acreage estimates for wilderness areas that have been designated by Congress as compiled by the agencies as of July 6, 2022. Acreages are estimates, since few (if any) of the areas have been precisely surveyed. In addition, the agencies have recommended areas for addition to the NWPS, and continue to review the wilderness potential of other lands under their jurisdiction, both of congressionally designated WSAs and under congressionally directed land management planning efforts. However, statistics on acreage in pending recommendations and on those being studied, particularly in the planning efforts, are unavailable.

As of July 6, 2022, Congress has designated 111.7 million acres of federal land in units of the NWPS, as shown in Table 2 and Figure 1. Wilderness areas have been designated in 44 states plus Puerto Rico; Connecticut, Delaware, District of Columbia, Iowa, Kansas, Maryland, and Rhode Island do not contain any designated wilderness areas. Just over half (52%) of this land—57.8 million acres—is in Alaska, and includes most of the wilderness areas managed by NPS (74%) and FWS (90%).⁵⁰ California has the next-largest wilderness acreage, with 15.3 million acres designated in the state. However, Washington has the largest percentage of federal land designated wilderness, with the 4.5 million acres of wilderness accounting for 38% of the federal land within the state. NPS manages the most wilderness acreage (44.3 million acres, 40% of the Wilderness System), followed by the Forest Service, which manages 36.7 million acres (33%). FWS manages 20.7 million acres (19%), and BLM manages the least wilderness acreage, 10.0 million acres (9%).

Figure 1. Designated Wilderness Areas and Federal Lands in the United States

Source: Created by CRS using data from Wilderness.net and the U.S. National Atlas. Notes: The federal lands depicted in this figure include all of the federally owned or administered land areas in the United States, including lands managed by the Department of Defense and Department of the Interior lands held in trust for Indian tribes.