Cahokia 'North Plaza' wetland

‘North Plaza’ of ancient North American city of Cahokia was likely inundated year-round.


Cahokia, one of the cores of Mississippian society along the great river, came into being in about AD 1050, grew rapidly for three centuries, then was abandoned during the 15th century. The largest archaeological site in North America, it lies in the American Bottom near the Mississippi immediately east of St. Louis. The imposing site was a major ceremonial center, ruled by an anonymous elite with powerful political connections along the Mississippi Valley.


Cahokia lies at the lowest point of the American Bottom, on an old meander scar of the river where creeks flood after heavy rains. Thousands of people congested the site for major festivals, at a location centered around mounds and what appeared to be major plazas.


The 'North Plaza' is defined by four surrounding mounds and has been investigated by geoarchaeologist Caitlin Rankin (pictured). Previous research had mainly focused on the mounds. Rankin took soil samples from the plaza, also the old river meander, and discovered that the area remained wet, indeed flooded, for much of the year.


In other words, it was not a plaza, but a wetland. Water was important at Cahokia, not only as a means of transport, but also the wetlands enabled them to grow a broad suite of cultivable plants. Rankin turned to traditional cosmology with its complex interactions between sky, water, and earth. She believes that the mounds emerged symbolically from the ever-changing watery landscape depicted by the plaza. This melded effectively with local creation myths associated with what was an exceptionally sacred location.


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Image: Caitlin Rankin within a trench dug in Mound 16, one of the mounds that delineate the ‘North Plaza’ of Cahokia.

Credit: Ann Merkle