Cahokia Interaction and Ethnogenesis in the Northern Midcontinent

The period from AD 900 to 1500 represents one of tremendous change in the northern Midcontinent. Driven by conditions of political and social asymmetry, environmental and economic variation, and climate change, the natives in the fan-shaped region anchored at St. Louis and stretching northeast along the course of the Illinois River valley formed a network of interacting yet diverse groups. In this region the social, political, and population dynamics generated by North America's first city, Cahokia, reverberated through the northern midcontinent at a level not experienced again until the impact of European expansion in the 1600s. The region pivoted on the American Bottom, an expanse of Mississippi River floodplain between the modern communities of Alton and Chester, Illinois. Stretching linearly about 160 kilometers, the floodplain is rich in backwater lakes, sloughs, swamps, wet and dry prairies, and assorted woodlands-a prime habitat for hunters, fishers, and gatherers as well as later farming folks.