The Wilderness Act of 1964 established the National Wilderness Preservervation System to protect wilderness areas on federal public lands, usually undeveloped or restored wildlands of greater than 5000 acres. Congress occasionally adds new areas to the system as recommended by the managing federal agencies or more often as proposed in citizen wilderness proposals.

More than 105 million acres have been designated as wilderness since the passage of the Wilderness Act. However, only 6.5 million acres are designated on land managed by the Bureau of Land Management (which manages most of the public land in the Sagebrush Sea). Of approximately 150 million remaining acres of the Sagebrush Sea, only about 2 million acres are protected as wilderness -- less than 2 percent of the region (see interactive wilderness map).

Development, roads, and "mechanized" vehicles and equipment (including bicycles) are prohibited in designated wilderness. Most forms of resource extraction are also prohibited--the glaring exceptions being preexisting livestock grazing and valid mining claims. However, grazing in wilderness may be evolving for the better. Heeding the public's growing displeasure for cows and cowpies in their wilderness areas, Congress established the first legislated cow-free wilderness on Steens Mountain in 2000, a sky island in southeast Oregon's Sagebrush Sea.

All BLM wilderness areas are now part of the new National Landscape Conservation System, a relatively new system established by BLM to manage its most treasured landscapes designated as wilderness areas, wilderness study areas, national conservation areas, national monuments, wild and scenic rivers, and national scenic and historic trails. See The Wilderness Society, State of the National Landscape Conservation System: A First Assessment