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 of 1816 was treaty signed by Ninian Edwards, William Clark, and Auguste Chouteau for the United States and representatives of the Council of Three Fires (united tribes of Ottawa, Ojibwa, and Potawatomi) residing on the Illinois and Milwaukee rivers, signed on August 24, 1816, and proclaimed on December 30, 1816. Despite the name, the treaty was conducted at Portage des Sioux, Missouri, located immediately north of St. Louis, Missouri.

By signing the treaty, the tribes, their chiefs, and their warriors relinquished all right, claim, and title to land previously ceded to the United States by the Sac and Fox tribes on November 3, 1804 (see, Treaty of St. Louis (1804)), In the treaty, the united tribes also ceded a 20-mile strip of land to the United States, which connected Chicago and Lake Michigan with the Illinois River. In 1848, the Illinois and Michigan Canal was built on the ceded land and, in 1900, the Chicago Sanitary and Ship Canal.

The specific land given up included:

The said chiefs and warriors, for themselves and the tribes they represent, agree to relinquish, and hereby do relinquish, to the United States, all their right, claim, and title, to all the land contained in the before-mentioned cession of the Sacs and Foxes, which lies south of a due west line from the southern extremity of Lake Michigan to the Mississippi river. And they moreover cede to the United States all the land contained within the following bounds, to wit: beginning on the left bank of the Fox river of Illinois, ten miles above the mouth of said Fox river; thence running so as to cross Sandy creek, ten miles above its mouth; thence, in a direct line, to a point ten miles north of the west end of the Portage, between Chicago creek, which empties into Lake Michigan, and the river Depleines, a fork of the Illinois; thence, in a direct line, to a point on Lake Michigan, ten miles northward of the mouth of Chicago creek; thence, along the lake, to a point ten miles southward of the mouth of the said Chicago creek; thence, in a direct line, to a point on the Kankakee, ten miles above its mouth; thence, with the said Kankakee and the Illinois river, to the mouth of Fox river, and thence to the beginning: Provided, nevertheless, That the said tribes shall be permitted to hunt and fish within the limits of the land hereby relinquished and ceded, so long as it may continue to be the property of the United States.

In exchange the tribes were to be paid $1,000 in merchandise over 12 years. The land was surveyed by John C. Sullivan and its land was originally intended as land grant rewards for volunteers in the War of 1812.

Today, Indian Boundary Park in West Ridge, Chicago commemorates this Treaty.