Cairo, Illinois

Historical marker location:

Urbandale, Illinois

( Marker is on Old U.S. 51 (Illinois Route 37) 1.1 miles south of Redman Road.)

Marker installed: 1986

Illinois was part of the French colonial empire, and the city of Cahokia, located near present-day Collinsville, was one of the largest pre-Columbian cities in North America. At its peak, around 1250 CE, Cahokia had a population of around 20,000 people.