The archaeological site Cahokia Mounds is not at or near the modern day town of Cahokia on your map, which was a French settlement. The mounds site’s on the Highway 111, the big mound next to US64 closer to Collinsville, by State Park Place in the north.
There are also some Indian mounds near Germantown, Ohio, as well as a great pair on Mt. Maria Carey.
I used to be an archaeologist. I really dig articles like this.
Oh.
I didn’t know that!