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 site is composed of a series of man-made earthen mounds. Cahokia is the largest archaeological site related to the Mississippian culture, and the term "Cahokian" is sometimes used to describe that culture. Cahokia Mounds State Historic Site was designated a World Heritage Site in 1982.
Cahokia was first settled around 650 during the Late Woodland period, but mound building did not begin there until about 1050 at the beginning of the Mississippian cultural period. The site was abandoned before 1400. The inhabitants left no written records, and the city's original name is unknown. The name "Cahokia" refers to an unrelated clan of Illiniwek people living in the area when the first French explorers arrived in the 1600s, long after Cahokia was abandoned.
Cahokia Wikipedia Entry