How St. Louis became known as 'Mound City' despite settlers razing those monuments

Cahokia Mounds State Historic Site in Collinsville hosts about 350,000 visitors each year. Much less well-known are the sites where 27 mounds once stood on the western side of the Mississippi River, just north of the Gateway Arch in St. Louis and farther west, including in Forest Park.

The mounds, carefully constructed and engineered by Indigenous people between 800-1350 CE, were destroyed by white settlers to make way for urban development during the 19th century. One monument remains in St. Louis today — Sugarloaf Mound, which is located about four miles south of the Arch between Interstate 55 and the Mississippi River.