Today the federal government owns and manages roughly 640 million acres of land in the United States. Four major federal land management agencies manage 610.1 million acres of this land, or about 95% of all federal land in the United States. These agencies are as follows: Bureau of Land Management (BLM), 248.3 million acres; Forest Service (FS), 192.9 million acres; Fish and Wildlife Service (FWS), 89.1 million acres; and National Park Service (NPS), 79.8 million acres. Most of these lands are in the West, including Alaska. In addition, the Department of Defense (DOD) administers 11.4 million acres in the United States, about 2% of all federal land. The remaining acreage, approximately 3% of all federal land, is managed by a variety of government agencies. Ownership and use of federal lands have stirred controversy for decades. Conflicting public values concerning federal lands raise many questions and issues, including the extent to which the federal government should own land; whether to focus resources on maintenance of existing infrastructure and lands or acquisition of new areas; how to balance use and protection; and how to ensure the security of international borders along the federal lands of multiple agencies. Congress continues to examine these questions through legislative proposals, program oversight, and annual appropriations for the federal land management agencies. Federal lands and resources have been important in American history, adding to the strength and stature of the federal government, serving as an attraction and opportunity for settlement and economic development, and providing a source of revenue for schools, transportation, national defense, and other national, state, and local needs. The formation of the U.S. federal government was particularly influenced by the struggle for control over what were then known as the "western" lands—the lands between the Appalachian Mountains and the Mississippi River that were claimed by the original colonies. The original states reluctantly ceded the lands to the developing new government. This cession, together with granting constitutional powers to the new federal government, including the authority to regulate federal property and to create new states, played a crucial role in transforming the weak central government under the Articles of Confederation into a stronger, centralized federal government under the U.S. Constitution. Subsequent federal land laws reflected two visions: reserving some federal lands (such as for national forests and national parks) and selling or otherwise disposing of other lands to raise money or to encourage transportation, development, and settlement. From the earliest days, these policy views took on East/West overtones, with easterners more likely to view the lands as national public property, and westerners more likely to view the lands as necessary for local use and development. Most agreed, however, on measures that promoted settlement of the lands to pay soldiers, to reduce the national debt, and to strengthen the nation. This settlement trend accelerated with federal acquisition of additional territory through the Louisiana Purchase in 1803, the Oregon Compromise with England in 1846, and cession of lands by treaty after the Mexican War in 1848. In the mid-to-late 1800s, Congress enacted numerous laws to encourage and accelerate the settlement of the West by disposing of federal lands. Examples include the Homestead Act of 1862 and the Desert Lands Entry Act of 1877. Approximately 1.29 billion acres of public domain land was transferred out of federal ownership between 1781 and 2015. The total included transfers of 816 million acres to private ownership (individuals, railroads, etc. ), 328 million acres to states generally, and 143 million acres in Alaska under state and Native selection laws. Most transfers to private ownership (97%) occurred before 1940; homestead entries, for example, peaked in 1910 at 18.3 million acres but dropped below 200,000 acres annually after 1935, until being fully eliminated in 1986. Although several earlier laws had protected some lands and resources, such as salt deposits and certain timber for military use, new laws in the late 1800s reflected the growing concern that rapid development threatened some of the scenic treasures of the nation, as well as resources that would be needed for future use. A preservation and conservation movement evolved to ensure that certain lands and resources were left untouched or reserved for future use. For example, Yellowstone National Park was established in 1872 to preserve its resources in a natural condition, and to dedicate recreation opportunities for the public. It was the world's first national park, and like the other early parks, Yellowstone was protected by the U.S. Army—primarily from poachers of wildlife or timber. In 1891, concern over the effects of timber harvests on water supplies and downstream flooding led to the creation of forest reserves (renamed national forests in 1907). Emphasis shifted during the 20 th century from the disposal and conveyance of title to private citizens to the retention and management of the remaining federal lands. During debates on the Taylor Grazing Act of 1934, some western Members of Congress acknowledged the poor prospects for relinquishing federal lands to the states, but language included in the act left disposal as a possibility. It was not until the enactment of the Federal Land Policy and Management Act of 1976 (FLPMA) that Congress expressly declared that the remaining public domain lands generally would remain in federal ownership. This declaration of permanent federal land ownership was a significant factor in what became known as the Sagebrush Rebellion, an effort that started in the late 1970s to strengthen state or local control over federal land and management decisions. Currently, there is renewed interest in some western states in assuming ownership of some federal lands within their borders. This interest stems in part from concerns about the extent, condition, and cost of federal land ownership and the type and amount of land uses and revenue derived from federal lands. Judicial challenges and legislative and executive efforts generally have not resulted in broad changes to the level of federal ownership. Current authorities for acquiring and disposing of federal lands are unique to each agency. The creation of national parks and forest reserves laid the foundation for the current federal agencies whose primary purposes are managing natural resources on federal lands—the BLM, FS, FWS, and NPS. These four agencies were created at different times, and their missions and purposes differ. As noted, DOD is the fifth-largest land management agency, with lands consisting of military bases, training ranges, and more. These five agencies, which together manage about 97% of all federal land, are described below. Numerous other federal agencies—the U.S. Army Corps of Engineers, Bureau of Reclamation, Post Office, the National Aeronautics and Space Administration, the Department of Energy, and many more—administer additional federal lands. The BLM was formed in 1946 by combining two existing agencies. One was the Grazing Service (first known as the DOI Grazing Division), established in 1934 to administer grazing on public rangelands. The other was the General Land Office, which had been created in 1812 to oversee disposal of the federal lands. The BLM currently administers more federal lands in the United States than any other agency—248.3 million acres. BLM lands are heavily concentrated (99.4%) in the 11 contiguous western states and Alaska. As defined in FLPMA, BLM management responsibilities are similar to those of the FS—sustained yields of the multiple uses, including recreation, grazing, timber, watershed, wildlife and fish habitat, and conservation. However, each agency historically has emphasized different uses. For instance, more rangelands are managed by the BLM, while most federal forests are managed by the FS. In addition, the BLM administers about 700 million acres of federal subsurface mineral estate throughout the nation. The Forest Service (FS) is the oldest of the four federal land management agencies. It was created in 1905, when responsibility for managing the forest reserves (renamed national forests in 1907) was joined with forestry research and assistance in a new agency within the Department of Agriculture (USDA). In 1891, Congress had authorized the President to establish forest reserves from the public domain lands administered by the Department of the Interior. Today, the FS administers 192.9 million acres of land in the United States, predominantly in the West, while also managing about three-fifths of all federal lands in the East (as shown in Table 5 ). Forest reserves—later renamed national forests—were originally authorized to protect the lands, preserve w ater flows, and provide timber. These purposes were expanded in the Multiple Use-Sustained Yield Act of 1960. This act added recreation, livestock grazing, and wildlife and fish habitat as purposes of the national forests, with wilderness added in 1964. The act directed that these multiple uses be managed in a "harmonious and coordinated" manner "in the combination that will best meet the needs of the American people." The act also directed sustained yield—a high level of resource outputs in perpetuity, without impairing the productivity of the lands. The first national wildlife refuge was established by executive order in 1903, although it was not until 1966 that the refuges were aggregated into the National Wildlife Refuge System administered by the Fish and Wildlife Service (FWS). Today, the FWS administers 89.1 million acres of federal land in the United States, of which 76.6 million acres (86%) are in Alaska. The FWS has a primary-use mission—to conserve plants and animals. Other uses (recreation, hunting, timber cutting, oil or gas drilling, etc.) are permitted, to the extent that they are compatible with the species' needs. However, wildlife-related activities (hunting, bird-watching, hiking, education, etc.) are considered "priority uses" and are given preference over consumptive uses such as timber, grazing, and mineral extraction. It can be challenging to determine compatibility, but the relative clarity of the mission generally has minimized conflicts over refuge management and use, although there are exceptions.