* Had __fertile soil__ surrounding the rivers, which allowed societies to __stay put__ and __farm__ and __develop__
* __Hopewell__ people:
* __4,000-6,000__ people
* __Traded__ with other regions
* __Cahokia__ people:
* __10,000-30,000__ people
* __Chieftains__ __centralized__ the __government__ and engaged in __trade networks__ from the __great lakes__