In the vast and fertile Mississippi River valley of southern Illinois the most complex societies in North American prehistory emerged around A.D. 800. The Mississippian peoples relied on corn horticulture and leadership from a priestly class. Earthen pyramids were erected for ceremonial activities. Wooden stockades with tall watchtowers were erected around the central plazas.

Cahokia, in the St. Louis area, is the largest of the Mississippian sites. By A.D. 1100 the Mississippian society was so large and complex, some archeologists have referred to the culture as a Native American empire, the first state or nation in North America. Aztalan was the northern most city of the Mississippian society.

The links below are to websites that describe other Mississippian sites throughout the eastern United States.