Mountain sheep remains are found regularly in foothill and mountain archaeological sites dating from Paleoindian to Late Prehistoric times. In the early stages of mountain sheep trap research program, only fragmentary bits of procurement complexes were encountered. In fact, the first catch-pen observed was initially thought to have been some sort of an unusual living structure. Only two species of extant mountain sheep are presently recognized in North America: Ovis canadensis and Ovis dalli. Mountain sheep apparently arrived in North America during the Illinoian glacial period. Mountain sheep remains have been found in numerous archaeological sites throughout Wyoming. The largest sample of Wyoming Late Pleistocene mountain sheep was recovered from Natural Trap Cave in northern Bighorn Mountains. The Black Mountain sheep trapping is one of a number of trapping complexes located along the east side of the Wiggins Fork River. The East Fork sheep trap consists of two catch-pens that share parts of the same drive line fences.