The name “Cahokia” comes from one of the constituent tribes of the Illinois Confederacy, a group of several semi-autonomous “tribes” or “villages” that occupied much of what is now the state of Illinois and parts of some of the surrounding states in the seventeenth and eighteenth centuries. Staunch allies of the French throughout most of the colonial period, the Illinois were among the hardest-hit by the various forces buffeting Native American groups in the wake of European contact, and they ended up suffering one of the most dramatic demographic collapses of the tribes we have substantial information on. Emily Blasingham, who did a detailed ethnohistoric study of Illinois population decline in the 1950s, concluded that the total population of the Confederacy at the time of French contact in the 1670s was around 10,000, which by 1800 had dwindled all the way to a mere 500 people. The descendants of the remaining Illinois ended up in northeastern Oklahoma, where they are now known as the Peoria (originally the name of one of the constituent tribes of the Confederacy along with the Cahokia, Kaskaskia, and others).
Most of the member tribes of the Confederacy, including the Cahokia and Peoria, spoke dialects of the Miami-Illinois language, part of the widespread Algonquian language family. One possible exception is the poorly known Michigamea, who joined the Confederacy in the early eighteenth century and had apparently lived before that somewhere further down the Mississippi River. While it has generally been assumed that the Michigamea also spoke Miami-Illinois, there is some evidence that they may actually have spoken a different language, possibly belonging to the Siouan family, before they joined the Confederacy. Be that as it may, the Illinois Confederacy as a whole was clearly primarily a group of tribes who lived near each other in the seventeenth century and spoke the same language.
The various Illinois groups moved around quite a lot during the colonial period in response to various threats and opportunities, but they had two main focuses of settlement: the upper Illinois River valley, especially around Starved Rock and Peoria Lake, and the American Bottom, along the Mississippi River between the mouths of the Illinois and Kaskaskia Rivers. The Cahokias consistently lived in the American Bottom for most of their recorded history, and gave their name to both the French settlement of Cahokia, which still exists as the town of Cahokia, Illinois, with its famous courthouse, and the nearby Cahokia Mounds.
The question of who built the Cahokia Mounds, and even if they were artificial at all, was hotly debated in the early history of American archaeology. Even after the early period of wild speculation in the nineteenth century had given way to a more systematic, realistic approach in the early twentieth, the answer remained unclear. In 1944 Donald Wray and Hale Smith, two archaeologists from the University of Chicago, proposed an answer with at least a surface degree of elegance and plausibility, namely, that Cahokia and other Mississippian sites in the region were the work of the Illinois Confederacy.
Wray and Smith had two main lines of evidence for this proposal: distributional and chronological. They noted, first, that the remains of what was then called the “Middle Mississippi Culture” corresponded pretty closely to the areas known to have been occupied by the Illinois in colonial times. Recall that the main areas of Illinois settlement were in the American Bottom and along the upper Illinois River, both areas that do indeed have substantial Mississippian remains. They also note that the general uniformity of Mississippian material culture suggests substantial social and political ties among the groups living in various parts of the region, such as would have been the case with a Confederacy such as that of the Illinois. Note that they don’t point to any specific material culture similarities between Mississippian sites and known Illinois sites, presumably because none of the latter were known at the time.
Their chronological argument takes a somewhat different tack. They note that other archaeologists had recently proposed that Mississippian societies dated to the sixteenth and seventeenth centuries, based on the lack of mention of some of the major mound sites by the early European explorers. Since the only occupants of the Mississippian parts of Illinois during this period are known to have been the Illinois groups, it follows that they must have been the Mississippians. They also go into some detail about certain sites showing contact between the Mississippians and the Oneota culture found primarily further north and tentatively identified with the speakers of Chiwere Siouan languages (i.e., Ioway, Oto, and Missouria). Since many Oneota sites have European trade goods and therefore clearly date to the contact period, Wray and Smith conclude that sites such as some in northern Illinois showing both Oneota and Mississippian traits support their chronological reconstruction. They also note the contacts between the American Bottom Mississippian sites and the southeast Missouri/northeast Arkansas area occupied historically by the Siouan-speaking Quapaw and connect this on somewhat shaky grounds to the Oneota as well.
We now know that this is all wrong, of course. Wray and Smith were working at a time when there was no way to get absolute dates for archaeological sites in the Midwest, and their chronological assumptions turned out to be totally unfounded when radiocarbon dating was invented a few years later and it turned out that the Mississippian sites were much older than the Illinois Confederacy and that in between there was a period when the American Bottom was part of the “Vacant Quarter” abandoned by the Mississippians. While it’s not impossible that some of the ancestors of the people who would later become the Illinois were involved in some Mississippian societies, there is no particular reason to connect them to the American Bottom specifically, and there is certainly lots of evidence indicating that the Illinois Confederacy itself came many centuries after the Mississippian phenomenon and had no direct connection to it.
While it’s easy to criticize ideas like this in hindsight, with the benefit of more and better information accumulated over several decades, it’s important to note that Wray and Smith’s ideas were actually challenged quite vigorously at the time by Waldo Wedel of the Smithsonian, who published a comment the following year aggressively pointing out the weakness of their assumptions and the dubiousness of their conclusions. Wedel points out that there are no known European trade goods associated with Mississippian sites in Illinois and that there is no evidence at all linking the Mississippian sites to the Illinois Confederacy despite their similar geographical distributions. He also challenges the idea that Mississippian societies in general are post-contact, and points out that while it was a possible interpretation of the evidence available at the time it was definitely not the only one and was lacking in actual supporting evidence. Further, he points out that while some Oneota sites are definitely post-contact, not all of the known sites had produced European trade goods, and it was not at all clear that all Oneota sites were historic rather than prehistoric. Also, he notes that the Quapaw stuff doesn’t make any sense and seems to be predicated on the assumption that since the Quapaw spoke a Siouan language and Oneota was thought to represent Siouan speakers the Quapaw could somehow be associated with Oneota despite the lack of any known Oneota sites in the Quapaw area. Wedel takes great pains to note that he is not criticizing the very idea of synthesizing archaeological data and organizing it into big historical narratives, as Wray and Smith have tried to do, just pointing out the flaws in the way they and some other archaeologists go about doing this. (This part is interesting because Wedel himself would go on to become one of the most important synthesizers of the archaeology of the Great Plains.)
As it turns out, Wedel was more or less completely right on every point he criticized Wray and Smith about, and the much more complete and accurate picture we now have of Midwestern archaeology has vindicated him. The point is not that Wray and Smith were wrong so much as that they were sloppy; it’s always going to be the case that even many very reasonable interpretations based on the best data available at one time will turn out to be wrong when better data appears, but not all interpretations at any given point in time are necessarily based on the best data or the most reasonable assumptions. This little dispute provides a particularly clear example of this general point.
Blasingham, E. (1956). The Depopulation of the Illinois Indians, Part I Ethnohistory, 3 (3) DOI: 10.2307/480408
Blasingham, E. (1956). The Depopulation of the Illinois Indians. Part 2, Concluded Ethnohistory, 3 (4) DOI: 10.2307/480464
Wedel, W. (1945). On the Illinois Confederacy and Middle Mississippi Culture in Illinois American Antiquity, 10 (4) DOI: 10.2307/275581
Wray, D., & Smith, H. (1944). An Hypothesis for the Identification of the Illinois Confederacy with the Middle Mississippi Culture in Illinois American Antiquity, 10 (1) DOI: 10.2307/275179