Mather Air Force Base (Mather AFB) is a closed United States Air Force Base located east of Sacramento, in the present-day city of Rancho Cordova on the south side of U.S. Route 50 in Sacramento County, California. (The base had already been closed before the city was incorporated in 2003.) Mather Field was one of thirty-two Air Service training camps established after the United States entry into World War I in April 1917. The Mather AFB land has various post-military uses including the 1995 Sacramento Mather Airport.