In 1940, the Camp Beale area consisted of grassland and rolling hills and the abandoned mining town of Spenceville. Then Marysville City officials encouraged the Department of War to establish a military facility in the area. The U.S. government purchased 87,000 acres in 1942 for a training post for the 13th Armored Division, the only unit of its kind to be entirely trained in California. Camp Beale also held training facilities for the 81st and 96th Infantry Division, a 1,000-bed hospital, and a prisoner of war camp. Dredge materials from the area's abandoned gold mines were used to build streets at the Camp.
As a complete training environment, Camp Beale had tank maneuvers, mortar and rifle ranges, a bombardier-navigator training, and chemical warfare classes. During WWII, Camp Beale had 60,000 personnel.
In 1948, Camp Beale became Beale Air Force Base (AFB), its mission to train bombardier-navigators in radar techniques. The Base established six bombing ranges of 1,200 acres each. The U.S. Navy also used Beale AFB for training. From 1951 on, Beale trained navigation engineers and ran an Air Base Defense School. These additional activities led to rehabilitation of existing Base facilities and construction of rifle, mortar, demolition, and machine gun ranges. In 1958 the first runway was operational.
One year later, the installation stopped being used as a bombing range and the U.S. Government declared portions of Camp Beale/Beale AFB as excess, eventually transferring out 60,805 acres. On December 21, 1959, 40,592 acres on the eastern side of the Base were sold at auction. An additional 11,213 acres was transferred to the State of California between 1962 and 1964, and now comprise the Spenceville Wildlife and Recreation Area. In 1964-1965, another 9,000 acres were sold at auction. In deeds for the former Camp Beale property, the Federal Government recommended that the property have surface use only.