McClellan Airport, California

McClellan is a diverse military industrial center being transitioned into civilian use. The 3,700-acre base has over 150 industrial buildings and many unusual high-tech weapons support facilities, including the only industrial nuclear reactor operated by the Department of Defense. One of the base's main tenants was the Air Force Technical Applications Center which operated a global network of nuclear event detection systems. In addition to intelligence and communications activities, the base performed logistics and supply missions, as well as aircraft and equipment maintenance. Until it was phased out as a military base in the late 1990's, McClellan employed over 15,000. It officially closed as military base in July 2001, though thousands continue to work there, mostly in civilian businesses that have moved in, and the airport is now called Sacramento McClellan Airport.