 In 1804, in the Treaty of St. Louis the Sac and Fox ceded Missouri north of the Gasconade River (but not their villages on the Mississippi River near Keokuk, Iowa).In 1808, in the Treaty of Fort Clark, the Osage Nation ceded all of Missouri and Arkansas west of the fort (now called Fort Osage in Jackson County, Missouri).The exact boundaries of the treaties were never formally surveyed.