The Desert National Wildlife Refuge is a protected wildlife refuge, administered by the U.S. Fish and Wildlife Service, located north of Las Vegas, Nevada, in northwestern Clark and southwestern Lincoln counties, with much of its land area lying within the southeastern section of the Nevada Test and Training Range. The Desert NWR, created on May 20, 1936, is the largest wildlife refuge in the lower 48 states of the United States, encompassing 1.615 million acres (6,540 km2) of the Mojave Desert in the southern part of Nevada. The refuge was originally established at 2.25 million acres. In 1940 840,000 acres were transferred to the Department of Defense.