The area is named for Lost Creek, a perennial stream that disappears and reappears before finally joining Goose Creek which empties into the South Platte River at Cheesman Reservoir just east of the Wilderness area. The entire water system of the area forms a watershed for the Platte River Basin. The area is notable for its many rock formations, natural arches, and rounded granite domes and knobs. These are contained in two ranges of low alpine foothills of the Rocky Mountains: the Kenosha Mountains and the Tarryall Mountains. Bison Peak is the highest peak in the wilderness.