The Treaty of St. Louis is signed on November 3, 1804, by Quashquame, a Sauk chief, and William Henry Harrison, the governor of Indiana Territory.

Quashquame maintains two large villages of Sauk and Meskwaki near the modern towns of Nauvoo, Illinois and Montrose, Iowa, and a village or camp in Cooper County, Missouri.

Black Hawk, a frequent visitor to Quashquame's village, will lament this treaty in his autobiography.

The Sauk and Meskwaki delegation had been sent to surrender a murder suspect and make amends for the killing, not to conduct land treaties.

Controversy surrounding the treaty will eventually cause the Sauk people to ally with the British during the War of 1812, and is the main cause of the Black Hawk War of 1832.