<P> Cahokia became the most important center for the people known today as Mississippians . Their settlements ranged across what is now the Midwest, Eastern, and Southeastern United States . Cahokia was located in a strategic position near the confluence of the Mississippi, Missouri, and Illinois Rivers . It maintained trade links with communities as far away as the Great Lakes to the north and the Gulf Coast to the south, trading in such exotic items as copper, Mill Creek chert, and whelk shells . </P> <P> Mill Creek chert, most notably, was used in the production of hoes, a high demand tool for farmers around Cahokia and other Mississippian centers . Cahokia's control of the manufacture and distribution of these hand tools was an important economic activity that allowed the city to thrive . Mississippian culture pottery and stone tools in the Cahokian style were found at the Silvernale site near Red Wing, Minnesota, and materials and trade goods from Pennsylvania, the Gulf Coast and Lake Superior have been excavated at Cahokia . Bartering, not money was used in trade . </P> <P> At the high point of its development, Cahokia was the largest urban center north of the great Mesoamerican cities in Mexico and Central America . Although it was home to only about 1,000 people before circa 1050, its population grew rapidly after that date . According to a 2007 study in Quaternary Science Reviews, "Between AD 1050 and 1100, Cahokia's population increased from between 1400 and 2800 people to between 10,200 and 15,300 people". an estimate that applies only to a 1.8 - square - kilometre (0.69 sq mi) high density central occupation area . Archaeologists estimate the city's population at between 6,000 and 40,000 at its peak, with more people living in outlying farming villages that supplied the main urban center . In the early 21st century, new residential areas were found to the west of Cahokia as a result of archeological excavations, increasing estimates of area population . If the highest population estimates are correct, Cahokia was larger than any subsequent city in the United States until the 1780s, when Philadelphia's population grew beyond 40,000 . Moreover, according to the same population estimates, the population of 13th - century Cahokia was equal to or larger than the population of 13th - century London . </P> <P> One of the major problems that large centers like Cahokia faced was keeping a steady supply of food . A related problem was waste disposal for the dense population, and Cahokia became unhealthy from polluted waterways . Because it was such an unhealthy place to live, Snow believes that the town had to rely on social and political attractions to bring in a steady supply of new immigrants; otherwise, the town's death rate would have caused it to be abandoned earlier . </P>

At the apex of cahokia the population stood at