Sawtooth National Forest spans 2,110,408 acres, almost all in Idaho, and has evolved since its creation as the Sawtooth Forest Reserve in 1905 into a broad mountain landscape managed in four units. Its terrain includes numerous ranges, more than 1,100 lakes, about 3,500 miles of rivers and streams, and habitats from sagebrush steppe to alpine tundra, supporting several species found nowhere else. People have lived here since at least 8000 BC, with the Shoshone present after 1700 AD. In the 20th century and beyond, recreation and conservation became central as mining disputes helped lead to major federal protections, including the Sawtooth National Recreation Area and several wilderness areas.