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
Palm Desert, California of the Desert, the local community college, which has expanded greatly in size since the campus opened in 1961 and one of the buildings was built by donations from the local Cahuilla Indian tribal nations. The state higher education system opened an extension campus duplex (the Indian Wells Education center for both California State University, San Bernardino and the University of California Riverside. The primary high school is Palm Desert High School (with 2200 students) which is part of the Desert Sands Unified School District. The main Middle School (with 1100 students) is Palm Desert Middle School, a charter school.