The Cahokia were an Algonquian-speaking Native American tribe and member of the Illinois Confederation. At the time of European contact with the Illini, they were located in what would become the states of Illinois, Iowa, Missouri, and Arkansas. The Cahokia, along with the Michigamea, were eventually absorbed by the Kaskaskia and finally the Peoria. After the U.S. government implemented its policy of Indian removal, they moved to Kansas Territory, and finally to present-day Oklahoma. The Cahokia tribe is now considered extinct.
The Tamaroa were closely related to the Cahokia.
Five Cahokia chiefs and headmen joined those of other Illinois tribes at the 1818 Treaty of Edwardsville (Illinois) in ceding to the United States half of the present state of Illinois.