Monk's Mound is the largest man-made earthen mound in North America at about 100 feet (30.5 meters) high and a base of 1,037 feet (316.1 meters) by 790 feet (240.8 meters).
During the Pre-Columbian era, Cahokia was for a time the largest North America city north of the Mesoamerican cities of central Mexico. Estimates of the city's peak population range from 8,000 to 40,000.
Cahokia Mounds State Historic Site protects the area of the mounds and is the site of ongoing archaeological excavations.
See also: Cahokia, Illinois