Treaty of Fort Clark

The Treaty of Fort Clark (also known as the Treaty with the Osage or the Osage Treaty) was signed at Fort Osage (then called Fort Clark) on November 10, 1808 (ratified on April 28, 1810) in which the Osage Nation ceded all the land east of the fort in Missouri and Arkansas north of the Arkansas River to the United States. The Fort Clark treaty and the Treaty of St. Louis in which the Sac (tribe) and Fox (tribe) ceded northeastern Missouri along with northern Illinois and southern Wisconsin were the first two major treaties in the newly acquired Louisiana Purchase. The affected tribes, upset with the terms, were to side with the British in the War of 1812. Following the settlement of that war, John C. Sullivan for the United States was to survey the ceded land in 1816 (adjusting it 23 miles westward to the mouth of the Kansas River to create the Indian Boundary Line west of which and south of which virtually all tribes were to be removed in the Indian Removal Act in 1830.

When Lewis and Clark began their explorations of the Missouri River in 1804, Pierre Chouteau of the Chouteau fur trading family in St. Louis, Missouri took Osage chiefs to meet Thomas Jefferson who promised to open a government sanctioned trading post (then called the factory which the Osage could sell their goods at a government set price (ostensibly to keep them from being exploited by individual traders). The trading post would also have a blacksmith to provide utensils for the Native Americans. In early 1808, Meriwether Lewis led a group to the site of Fort Osage near Sibley, Missouri where they built the fort on a bluff above the Missouri River. Pierre Chouteau went about 150 miles south to Neosho, Missouri where the Osage had their principal village on the Osage River and brought the chiefs to Fort Osage. There they were presented with the terms of the treaty.

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