The pre-Columbian settlement at Cahokia was the largest city in North America north of Mexico, with as many as 20,000 people living there at its peak. Cahokia was a city that, at its peak from A.D. 1050-1200, was larger than many European cities, including London.
Answer:
The name of the city you are describing is Cahokia.
Explanation:
Cahokia was the largest city that existed from the 600s-1400s and was the largest city in North America prior to European contract.