The Treaty of St. Louis is the name of a series of treaties signed between the United States and various Native American tribes from 1804 through 1824.
The fourteen treaties were all signed in the St. Louis, Missouri area.
The Treaty of St. Louis (also known as the Treaty with the Osage or the Osage Treaty) was signed on September 25, 1818, in St. Louis between William Clark of the United States and members of the Osage Nation.
Based on the terms of the accord, the Osage ceded all territories to the United States beginning at the Arkansas River and ending at the Verdigris River.
The specifications of the lands ceded to the United States are found in Article 1 of the accord: