Desert bighorn sheep establish two desert areas in southwestern Arizona to help preserve the desert bighorn sheep: Cabeza Prieta National Wildlife Refuge and the Kofa National Wildlife Refuge. In 1941, the San Andres National Wildlife Refuge in New Mexico was added. Desert bighorn sheep populations have trended upward since the 1960s when their population was estimated at 6,700-8,100. The upward trend was caused by conservation measures, including habitat preservation. In 1980, desert bighorn sheep populations were estimated at 8,415-9,040. A state-by-state survey was conducted a few years later and estimated the overall US desert bighorn sheep population at 15,980. The 1993 estimate of
Tule Desert (Nevada) at the south end of the Tule Springs Hills. Access is via a county road east from Lyman Crossing along the Union Pacific railroad line between Carp and Elgin in Meadow Valley Wash. The road continues on to the south between the Mormon and East Mormon mountains to connect with Interstate 15 in Nevada at exit 100 west of Mesquite in Clark County. Tule Desert (Nevada) The Tule Desert is located in southeastern Nevada in Lincoln County, near the Utah state line. The desert lies northeast of the Mormon Mountains, south of the Clover Mountains and west of the Tule