The High Rock Lake Wilderness includes the northern portion of the Calico Mountains a typical north -south trending Great Basin mountain range. Elevations in the wilderness range from 4,000 to 7,000 feet. Sagebrush is the dominant vegetation type, with saltbush and greasewood occurring at the lower elevations. Several canyons also contain willows, cottonwoods, aspens and other riparian species. The Wilderness was named for the usually dry High Rock Lake in the northwestern part of the Wilderness. The lake occasionally fills with waters flowing from High Rock and Little High Canyons. The lake was formed when a massive rockslide occurred thousands of years ago blocking the mouth of Box Canyon and diverting flows through Fly Canyon further to the north. A portion of the Applegate-Lassen Emigrant Trail crosses through the northern portion of the Wilderness. Wildlife that inhabits the area includes mule deer, California bighorn sheep, pronghorn antelope, mountain lion, kit fox, coyote, and sage grouse.