This marker near Brownson recalls the Sioux Ordnance Depot, later the Sioux Army Depot, which the Army opened on March 23, 1942, on 19,771 acres northwest of Sidney. Its 801 earth-covered igloos stored ammunition through World War II, Korea and Vietnam until the depot closed on June 30, 1967; many igloos are now used for private storage. The depot's 1942 Fire and Guard Headquarters is on the National Register.