Density in the pre-Columbian United States: A look at Cahokia

Cahokia mural

Cahokia is one of the largest historical American cities you’ve probably never heard of. Peaking around 1250 CE, Cahokia is considered the first Mississipian settlement, a culture which spread to throughout the central and southeastern United States. The city’s inhabitants built over 100 mounds, eighty of which remain. One of them still towers 92 feet over the surrounding fields and is easily visible from the scratched postage-stamp windows of St. Louis’ Gateway Arch. With somewhere between 10,000 to 15,000 people, it held the record for the largest American city until around 1800, when Philadelphia finally overtook it.

With that many people crammed into just under three-quarters of a square mile—the estimated size of the city’s neighborhoods—it may sound like Cahokia was as cramped as the slums of Upton Sinclair’s Chicago. But it probably didn’t feel that way. Sweeping plazas and towering mounds added nearly three square miles of open space, keeping much of the city open and airy like Baron Haussmann’s Paris. Yet unlike the city on the Seine’s astronomical modern density of 58,890 people per square mile, Cahokia’s population lived at a positively suburban 1,000 to 1,500 people per square mile, thanks to the plazas and mounds.

Archaeological excavations in the area suggest that Cahokia proper can be bounded by one circle two miles in diameter and another about 1,200 yards in diameter. Of that space, less than 20 percent was devoted to housing, which was clustered in small groups. The rest of the area was tied up in grand plazas and towering earth mounds. So while the density was higher in the housing clusters—about 5,600 to 8,500 people per square mile—open space was never far away. Cahokia may have been bustling for the time, but it was probably a pleasant place to live.

Flipping through the pages of a book chapter on Cahokia’s population, I was struck by the way archaeologists used population density not as a final product, but a building block. By excavating only small areas—sampling the landscape, in effect—they estimate both the number of people that occupied a certain area (based on the size and number of houses) and the extent of housing within the settlement. They then multiply the two together and get a reliable estimate of its population. Modern population density is derived the other way around, built from census data and community extents.


Pauketat, Timothy R., & Lopinot, Neal H. (1997). Cahokian Population Dynamics Cahokia: Domination and Ideology in the Mississippian World, 103-123 Other: 978-0803237087 University of Nebraska Press, Lincoln, Nebraska.

Photo of interpretive center mural by emilydickinsonridesabmx.

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The woods that were

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    1. Maybe by today’s standards, but the sentiment I got from reading the chapter and some other background material is that this was city-level back in those days. And you’re right, it may not be the largest historical city you haven’t heard of, but it’s probably the largest historical American city you’ve never heard of. (Updated the lede to reflect that.)

  1. Not only have I heard of Cahokia, but I went to college there (although the college’s operations moved over to Saint Louis a few years ago). I knew the town had some historical significance, but not to this extent. I’m a bit curious about the actual geographic size of the town, however. My school was near the historical center of town, but the Cahokia Mounds are about 7 miles north, beyond East St. Louis. If the supposed diameter of the town proper was only 2 miles, what was between “downtown” and the mounds? More mounds? Other settlements? Hunting grounds? Does that area get included in the density calculation?

    1. Archaeologists often list the “downtown” of Cahokia as Monks Mound, the largest mound in the settlement. More mounds and plazas occupied the space between housing clusters. Those areas are not included in the housing cluster density calculations (5,600 to 5,800 people per square mile), but I did include them when estimating the density of the entire settlement (1,000 to 1,500 people per square mile) as I think it captures more of what the place felt like.

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    1. That’s true, but I was talking about American in the an even more limited sense (what some people call “USian”, though that doesn’t quite roll off the tongue). There were plenty of large South American cities (with all deference to your work).

  3. Hiking to the top of Monks Mound on a hot, humid day is rather challenging, but the view is cool. Some of my students replaced the railroad-tie stairs some years back, and found all sorts of old Colonial and Civil War-era stuff (buttons and things). The most interesting thing about Mississippian culture was its trade ties to the Maya.