Cahokia MoundsAccording to archaeological finds, the city of Cahokia was inhabited from about A.D. 700 to 1400. At its peak, from A.D. 1050 to 1200, the city covered nearly six square miles and 10,000 to 20,000 people lived here. Over 120 mounds were built over time, and most of the mounds were enlarged several times. Houses were arranged in rows and around open plazas, and vast agricultural fields lay outside the city.