From AD 600-1400, the Mississippian native Americans had a massive city near the present site of St. Louis, MO. It was one of the world's largest cities at the time, and was the largest pre-Columbian city north of the Aztec civilization with a population of about 30,000 people. But by AD 1400, before any European settlers ever stepped foot on the continent, it died out completely.

My question is, why was the city of Cahokia ultimately abandoned?

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    Just a cavil re "one of the world's largest cities at the time". Kaifeng, Chang An, Baghdad, Constantinople, Cordoba all above 500K, 'at the time'. Sure, Cahokia was extraordinarily big...but only in comparison to the tiny villages in the rest of the midwest and east.
    – Mitch
    Jun 15, 2013 at 15:06
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    @Mitch - According to my handy-dandy New Penguin Atlas of Medieval History, the largest cities in the west at the time (Ghent, Paris, Genoa, Milan, Venice, Florence, Constantinople, Tabriz, and Cairo) were all in the 50-125,000 range at around 1346. However, there were indeed oodles (33 by my count) of smaller cities in the same 23-49K range he's putting Cahokia in.
    – T.E.D.
    Jun 15, 2013 at 16:57
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    @T.E.D.: I'm just looking at wikipedia for my reference. But either way, 30K is not "one of the world's largest" especially when it is among oodles in that second tier. Understanding is not helped by misdirected comparison. Also, I think your reference is somehow missing Baghdad and East Asia.
    – Mitch
    Jun 15, 2013 at 17:21
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    It's not about that city specifically, but you likely want to have a look at Collapse, by Jared Diamond.
    – o0'.
    Sep 3, 2015 at 13:14
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    @Lohoris - I probably should have credited Collapse as a source in my answer. That was my main source for the 4th paragraph.
    – T.E.D.
    Sep 3, 2015 at 13:36

3 Answers 3


Reading through the available literature there appear to be three main theories for the cause of the decline (that I'd consider credible anyway): environmental degradation, warfare and disease, and climate change. Typically these are cited as a group of possibly complementary possible causes.

The main idea behind the environmental degradation theory was that Cahokia, as structured in 1200, consumed a tremendous amount of wood, and after a few hundred years of over-harvesting the area simply ran out.

Deforestation required longer walks for firewood. Charred remains show that Cahokians burned oak and hickory in the early years but used energy-poorer soft woods later, a sign of problems, Iseminger says. The stockade alone required as many as 20,000 poles.

I'm kind of skeptical of this as a sole or primary cause. Civilizations destroyed by their own hands this way tend to either be very isolated (like the Easter Islanders), or working very marginal agricultural land (like the Maya). It could certainly have contributed though.

As to warfare: there does appear to be more sign of defensive structures both at Cahokia, and at neighboring Mississippian towns, starting at around 1200. While this no doubt contributed, IMHO increased warfare tends to be a symptom of other problems (generally a sudden shortage of resources), rather than a root problem itself.

There has also been evidence found in remains at the site of endemic disease problems (and no evidence of provisions for sanitation). However, disease is a problem that tends to go hand-in-hand with large cities. IMHO it would be far more remarkable if they didn't find evidence of widespread disease.

Now for the Climate Change theory. One thing that does jump right out at one is the timing. It turns out that there was one other agriculture-based civilization that was wiped out of North America at seemingly the exact same time: The Greenland Vikings. They were a (somewhat) literate people, who coincidentally went into decline around 1200 and were last heard from in 1410. There is still some debate over their decline as well, but the preponderance of evidence points to the global cooling period known as the Little Ice Age.

Based on radiocarbon dating of roughly 150 samples of dead plant material with roots intact, collected from beneath ice caps on Baffin Island and Iceland, Miller et al. (2012)[12] state that cold summers and ice growth began abruptly between AD 1275 and 1300, followed by "a substantial intensification" from 1430 to 1455 AD

The colder temperatures and shorter growing seasons would have made agriculture in marginal areas untenable. This is what records indicate happened to the Vikings of Greenland.

Now the staple crop of the Mississippian region was Maize. This is a crop ultimately of Central American origin which took thousands of years to evolve variants capable of being intensively harvested in temperate regions. While Cahokia may not have been at the extreme northern boundary of viable high-intensity maize production, it was certainly near it. A prolonged period of cold weather, which we know for a fact happened around then, would have made the populations Cahokia had at its peak simply unsustainable.

If you check around, this is a theory that pretty much every source mentions prominently. While I can't find anyone saying they believe it is the primary cause, the fact that everyone brings it up, many of them most prominently, is probably significant.

So while there are a variety of theories and explanations, the one that seems the most compelling (if one is forced to pick) as a primary cause would be the Little Ice Age.

(note: One particularly useful source I found was Cahokia Mounds: America's First City. If you're interested in this topic, you may consider picking up a copy)

  • I'm a bit skeptical whether warfare had anything to do with Cahokia's degradation. Some (very weak & unreferenced) sources I read claim the defensive structures were mostly ritualistic, and that there's no other sign of warfare.
    – yannis
    Jun 15, 2013 at 15:45
  • @YannisRizos - Quite. I saw the same things you did. However, as I said, even if it was a factor, I'm fairly convinced there would have been a deeper cause behind the warfare. My head says probably lack of food due to the Little Ice Age. My heart however is tempted to say it was just the badass (Siouxan) Osages moving into their territory. This was Osage territory when the historical record opens, and they happen to be my tribe. :-)
    – T.E.D.
    Jun 15, 2013 at 17:12
  • @T.E.D. - are you trying to take ownership in what amounted to a genocide, if the theory from your comment is true? :))) Great answer, +1
    – DVK
    Jun 19, 2013 at 17:13
  • Hmmm..Looking into this a bit further, it appears the Osage Tribe claims the mounds. I'm not sure how strong that claim is, but I might not get myself in good smell with the tribe for implying otherwise. This deserves further study...
    – T.E.D.
    Jun 20, 2013 at 3:35
  • @DVK - There's recently been some studies on this, and in fact linguistics and archeology are backing up my Osage ancestors on this matter. This is actually really useful information because it means we know exactly where their descendants went when Cahokia died out.
    – T.E.D.
    Jan 21, 2022 at 1:47

Environmental degradation, warfare and disease, and climate change can, of course, affect the decline/success of any civilization. Overall, there can be many reasons why the Cahokia tribe declined, as T.E.D has stated above. I say that the main two possibilities of the Cahokia tribe's decline was climate change and population and disease.

As stated in the article "Cahokian Indians: America's Ancient Warriors":

As Cahokia’s strength grew, war parties were sent from the capital to further expand the borders of Cahokian control.

Basically, you can gather from this statement that the Cahokia's tribe was large and growing in number. Take into account that around the time the Roman Empire was still thriving, it too had a large population which then led to its downfall. In short, population can be a huge factor in the decline of the Cahokians. With a large population, usually sanitation can be a hard thing to keep on top of and this brings diseases.

Another possibility of the Cahokia tribes downfall could be climate change. According to the article "Cahokia's Boom and Bust in the Context of Climate Change":

Benson, Berry, Jolie, Spangler, Stahle, and Hattori (2007) have suggested that mid-twelfth- and late-thirteenth-century decadal-scale droughts may have impacted Native Americans across much of the contiguous United States.

If there are constant droughts, this can make it difficult to grow crops and feed your tribe.

Furthermore, I agree that climate change could have contributed to the decline of the Cahokia tribe, however, the population was probably a factor as well.


This question solicits theories, but for the record I will state the simple fact that when cities disappear it is almost always because they are attacked by a stateless invader and destroyed. By a "stateless" invader I mean a migratory or transient group that does not maintain its own cities. If an invader has its own cities and systems, then it will usually coopt other cities it conquers and add them to its system thus "reducing" them. If the invader has no cities, however--is a horde, in other words--they have no capacity to do this and often just obliterate whatever cities they encounter.

Comment about economics:

Smaller cities, created specifically to extract a resource, can die out naturally, creating "ghost towns". Some have argued that "Cahokia" died out when wood in the surrounding area was exhausted. I doubt that this is the case because the city was quite sizable and this indicates that a self-perpetuating culture existed there. A loss of wood might cause the city to decline, but would not by itself cause abandonment, since the motive force of the city, the culture, is still there. If you argue that wood was the motive force and that it was an economic town after all, the problem is that there are many thousands of such forests all over North America, so in that case there would have been thousands of Cahokias, not just one. The uniqueness of the city indicates the presence of some lost culture.

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    This sounds like another vote for my "Osages did it" theory. :-)
    – T.E.D.
    Nov 11, 2015 at 15:15
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    ...but as for the the "there would have been thousands of Cahokias", there actually sort of were. Or at least hundreds. The Cahokia was just the biggest found (so far).
    – T.E.D.
    Nov 11, 2015 at 15:19

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