Military installations along the route of the Overland Mail Company, from east to west, during the period in which the route was being run: Fort Smith, Arkansas – 1817-1871 Fort Washita, near Colbert’s Ferry, Indian Territory – 1843-1858 Fort Belknap, Texas – 1851-1859 Camp Cooper, Texas, near Fort Griffin – 1856-1861 Fort Phantom Hill, Texas … More Forts on and near the Route