McCook Army Air Base, activated April 1, 1943, was one of 11 Army Air Force training bases in Nebraska during World War II. Some 15,000 servicemen and 500 civilians were stationed here. The 2,100 acre base included three 150 by 7,500-foot concrete runways, five hangars, and barracks for 5,000 men. The base closed December 31, 1945.