Kofa National Wildlife Refuge preserves a vast Sonoran Desert landscape in southwestern Arizona, including the Kofa Mountains and much of the Kofa Wilderness, one of the state’s largest wilderness areas. Established in 1939 primarily to protect desert bighorn sheep, it grew from a conservation campaign sparked after Major Frederick Russell Burnham warned that fewer than 150 sheep remained in Arizona’s mountains. The refuge now supports an important bighorn herd that has supplied animals for relocation elsewhere. Kofa is also notable for diverse desert wildlife, rare plants such as the Kofa Mountain barberry and Arizona’s native desert fan palm, and for traces of mining history and World War II desert training.