Cahokia is the site of an ancient Native American city near Collinsville, Illinois, across the Mississippi River from St. Louis, Missouri in the American Bottom floodplain. The city was the center of a pyramid civilization in the center of what is now the United States.

Cahokia is the largest archaeological site related to the Mississippian culture, and the term “Cahokian” is sometimes used to describe that culture. The Mississippians developed advanced societies in eastern North America before the arrival of Europeans.