Fort Riley is a United States Army installation located in North Central Kansas, on the Kansas River, also known as the Kaw, between Junction City and Manhattan. The Fort Riley Military Reservation covers 101,733 acres (41,170 ha) in Geary and Riley counties. The Fort consists of six functional areas, including the Main Post, Camp Funston, Marshall Army Airfield (MAAF), Camp Whitside, Camp Forsyth, and Custer Hill. The portion of the fort that contains housing development is part of the Fort Riley census-designated place, with a residential population of 9,230 as of the 2020 census. The ZIP Code is 66442.