Desert National Wildlife Refuge in southern Nevada, north of Las Vegas, is a protected Mojave Desert landscape administered by the U.S. Fish and Wildlife Service. Covering 1.615 million acres across Clark, Lincoln, and Nye counties, it is the largest wildlife refuge in the contiguous United States. Created on May 20, 1936, and reduced in 1940 after acreage was transferred to the Department of Defense, it includes six major mountain ranges and broad valleys whose dramatic elevation changes create varied climates and plant communities. Its central mission is conserving desert bighorn sheep and their habitat, while also supporting recreation and visitor access through Corn Creek Field Station.