Cahokia

Cahokia is the Mississippian city whose earthen mounds rise from the American Bottom, the floodplain of the Mississippi opposite the later town of St. Louis, close to where the Missouri and Illinois rivers meet. Around 1050 its builders laid out a planned city with a Grand Plaza and dozens of mounds, and by about 1100 it held perhaps 15,000 to 20,000 people, trading copper, shells and Mill Creek chert with the Great Lakes and the Gulf Coast. It was the largest urban centre north of Mexico, and its original name is unknown.

By 1337 the city was in its last decades. From the late twelfth century people had been leaving, a walled compound had burned around 1160, and a palisade built about 1175 was rebuilt again and again around a smaller core. By 1350 the city was abandoned, and Cahokians went south into the Cairo Lowlands and the Central Mississippi Valley. For two centuries the surrounding country stood nearly empty, in what scholars call the Vacant Quarter. In the mid-seventeenth century Algonquian-speaking people of the Illinois Confederation moved in, among them the Cahokia tribe that lent its name to the mounds. French families later claimed the land, and around 1809 Trappist monks lived on the grounds.