The Wilderness consists of a large area of broad volcanic uplands dissected by the deeply cut drainages of High Rock and the East Fork of high Rock Canyons. Elevations in the Wilderness range from 4,900 to 6,600 feet. The main vegetation type is sagebrush, with willows and one small stand of aspens occurring in the canyons. The canyons are relatively well watered and support meadow complexes and other riparian vegetation. Remnants of early homesteads can be found in the East Fork of High Rock Canyon. Wildlife in the area includes California bighorn sheep, mule deer, pronghorn antelope, mountain lions, coyotes, and sagegrouse. The canyons also provide outstanding habitat for nesting raptors. The Applegate-Lassen Emigrant Trail is located in High Rock Canyon which forms the western boundary for the area.