Fort Leavenworth (/ˈlɛvənˌwɜːrθ/) is a United States Army installation located in Leavenworth County, Kansas, in the city of Leavenworth, roughly 20 miles northwest of Kansas City. Built in 1827, it is the second oldest active United States Army post west of Washington, D.C., and the oldest permanent settlement in Kansas. Fort Leavenworth has been historically known as the "Intellectual Center of the Army."