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The Mystery of Cahokia

The Mystery of Cahokia

The Mystery of Cahokia

WHEN you think of historic cities, which ones come to mind? Rome, London, Paris? What about Cahokia? ‘Cahokia?’ you might ask. Yes, Cahokia​—located in Illinois, eight miles [13 km] east of St. Louis, Missouri, U.S.A. * Large, sophisticated, and well planned, it ranked as an outstanding American Indian city for 500 years. At the height of its civilization, about 1150 C.E., Cahokia was bigger than either London or Rome of that time.

Encompassing more than five square miles [13 km2], according to one source, Cahokia “was unquestionably the largest prehistoric urban center north of Mexico.” (Encyclopedia of North American Indians) In addition, all along the Mississippi River valley are the remains of earthen mounds​—silent reminders that a thriving civilization once existed here. In fact, St. Louis itself was nicknamed Mound City before urban expansion overwhelmed the 26 mounds within its borders.

A Protected Historic Site

Some Native Americans regard Cahokia as a starting point from which many tribes can trace their origin. The book The Native Americans states that “descendants of the mound-building Mississippians became the Chickasaws, the Seminoles, and the Choctaws.” Another source says that they were the ancestors of the Creek, the Cherokee, the Natchez, and others.

Originally, Cahokia included 120 earthen mounds. But now, after many years of farming and urban expansion in the area, only 80 remain. Of these, 68 lie within the boundaries of the present 2,200-acre [890 hectare] site.

Since 1925, Cahokia has been protected as an Illinois State Historic Site. And in 1982 the United Nations Educational, Scientific, and Cultural Organization designated Cahokia Mounds as a World Heritage site because of its importance in understanding the early history of North America.

Why Here?

As early as 700 C.E., the area around Cahokia was inhabited by Indians of the Late Woodland culture. However, the mounds were not built until about 200 years later. Why was Cahokia built here? For the same reasons that St. Louis was built nearby. The site is close to the intersections of three major rivers​—the Mississippi, the Missouri, and the Illinois—​on the fertile river floodplain that geologists call the American Bottom.

The rivers and their tributaries were filled with fish and migrating waterfowl. The surrounding woodlands provided not only lumber but also game, especially white-tailed deer​—a primary source of meat. Other resources, such as basalt, red ocher, galena, and granite, came from the nearby Ozark Plateau. And the neighboring prairies provided plenty of tall grasses for use in building homes and other structures for a peak population of perhaps 20,000 or more. The floodplain itself produced an abundance of crops, including corn, amaranth, pumpkins, squashes, and sunflowers. The Cahokians could also gather pecans, hickory nuts, blackberries, and wild plums. Moreover, the rivers allowed them to carry on extensive trade in all directions. Seashells from the Gulf of Mexico, copper from the North American Great Lakes region, and mica from the Appalachian Mountains have all been discovered at Cahokia.

The Life and Beliefs of the Cahokians

In the visitor center at the site is a life-size display depicting typical daily activities in Cahokia, including skinning deer and grinding corn. Knowledge of corn cultivation, combined with access to other natural resources, was the cornerstone of Cahokia’s civilization.

One archaeologist described Cahokia as “a North American Jerusalem,” since religion appears to have permeated every aspect of its society. Another source says that “at its peak (A.D. 1000-1150) Cahokia was home to a highly centralized theocracy.” Artifacts discovered here indicate that in the Cahokian’s view, religion and society were inseparable. According to the book Cahokia​—City of the Sun, “their world was one of opposing forces—​dark and light, order and anarchy, good that was rewarded and evil that was punished.”

The Cahokians believed in an afterlife. Thus, the dead were buried with honor and often with elaborate ritual, especially among the elite. Some of their mounds were tombs and may have played a role similar to that of the pyramids of the Egyptian Pharaohs.

A Tour of the Mounds

Let us take a closer look at the mounds. Though they vary in size and shape, all are made of earth, which was transported in baskets to the mound construction sites. It is estimated that, in all, some 50 million cubic feet [1.5 million m3] of soil was moved in this manner!

There are three types of mounds: linear ridgetop mounds, which may have served as location markers, although some contain graves; conical mounds, which may also have been used for burial; and platform mounds, which range in height from a few feet [about a meter] to a hundred feet [30 m] and served as a base for constructing buildings. Platform mounds were often topped with temples, council lodges, or the dwellings of members of the elite.

Our first stop, designated Mound 72, was built on top of three smaller burial mounds. It is 140 feet [43 m] long, 72 feet [22 m] wide, and barely 6 feet [2 m] high. As mounds go, it is not very large, but it has yielded an incredible cache of valuable artifacts that shed light on Cahokia. The mound contained the tomb of one man who may have been a prominent leader, judging by the nearly 20,000 Gulf Coast shell beads that were laid out beneath him. In addition, grave offerings, including 800 arrowpoints, 15 concave stones used to play Indian games, a large pile of mica, and a roll of copper, were buried with him. Also, about 300 other people, mostly young women, were entombed here​—many possibly as human sacrifices.

Monks Mound​—Why So Special?

Now let us head north across Cahokia’s central plaza toward Monks Mound, named after the Trappist monks who lived nearby in the early 1800’s and actually gardened on the mound. It is the largest mound at Cahokia and is shaped like a truncated pyramid but with four terraces at various levels. It was built in as many as 14 stages, and it is believed that the construction took place between 900 and 1200 C.E. The mound’s base covers more than 14 acres [6 hectares], “larger than that of any pyramid in Egypt or Mexico.” The mound rises to a height of 100 feet [30 m] and is over 1,000 feet [300 m] long, making it the largest pre-Columbian earthen construction in the Western Hemisphere. On the south side of Monks Mound is a long ramp leading up to the flat terraces. Excavations suggest that there were stairs on this ramp.

No commoner would have been allowed to ascend to the top of these stairs. At the summit stood a large building​—the dwelling place of Cahokia’s ruler, a chieftain known as the Great Sun. “There, the chief and his priests probably performed religious rituals and administrative duties, surveyed their domain, and greeted emissaries from the hinterlands,” states Cahokia​—City of the Sun. From this vantage point, the chief could also keep an eye on the various communal structures below, including council lodges, granaries, buildings for food storage, sweat lodges, charnels, and the citizens’ dwellings.

The chief could also monitor the stockade that encircled the city, with its numerous lookout towers. The two-mile-long stockade wall was rebuilt three times, each rebuilding requiring as many as 20,000 trees. Some archaeologists believe that it served as a social barrier. But likely it was also built for defense. Who the Cahokians’ enemies may have been, however, is a mystery.

What Happened to the Cahokians?

Another mystery also remains. By 1500 C.E., Cahokia had been abandoned. What happened? Theories abound. Evidence unearthed so far does not show signs of any epidemic, invasion, or natural disaster. Perhaps a combination of factors, including climatic change and deforestation, brought drought, hunger, and social upheaval.

Some scientists believe that Cahokia may have suffered from many of the same social ills that plague modern cities​—pollution, overcrowding, inadequate waste disposal, and perhaps even civil strife. But not having the Cahokians present to describe their way of life, we are left with many unsolved mysteries.


^ par. 2 The name Cahokia was given to the site during the 1800’s. Some believe that the word means “city of the sun.” Other experts believe it means “wild geese.” There are no written records to indicate what the local people called themselves or their city.

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There is much speculation about the origin of the Cahokia civilization, and experts disagree on the answer. Francis Jennings, director emeritus of the Newberry Library Center for the History of the American Indian, is convinced that early colonists from Mesoamerica brought their maize and their architecture to the Mississippi Valley. He writes: “The colonists established apparent commercial superiority over indigenous tribes in the Mississippi Valley on a scale that looks on the map very like an empire. They brought from Mesoamerica the habit of building truncated pyramids and of putting temples and administrative structures on the topmost platforms.”

However, Jennings admits that much remains uncertain. “Archaeologists dispute whether the Mississippians in fact were colonists from Mexico, and they dither a lot on the issue while failing to offer a credible alternative.”

George E. Stuart, in his book Ancient Pioneers​—The First Americans, states: “To many archaeologists and art historians, the platform mounds, carefully arranged around plazas,” and some of the pottery “demonstrate clear influences, perhaps indirect, from Mesoamerica—​as do the strains of maize and beans present at the sites.” However, a seed of doubt is sown with his words, “no single artifact of undisputed Mesoamerican manufacture has ever been found in the Southeast.” Thus, the mystery remains​—who influenced the inhabitants of Cahokia? Was it colonists from Mesoamerica? Time and archaeology might one day supply an answer.


Arrowpoints and stones from Mound 72

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Another unique feature of Cahokia is a series of “perfect circles where massive, evenly spaced posts once protruded from the flats.” (National Geographic magazine, December 1972) These have been called woodhenges because of their similarity to the ancient stone solar calendar at Stonehenge in England.

One woodhenge has been restored. It is a circle, 410 feet [125 m] in diameter, of 48 enormous red-cedar posts and is thought by some to have served as a solar observatory. The posts are “aligned with the points of the compass, and so arranged that a forty-ninth post outside the circle permitted an observer within to view the sunrise at the equinoxes and solstices in A.D. 1000.”

Archaeologists have been able to define the purpose of only three of the posts. One post marks the equinoxes, the first day of spring and of fall, when the sun rises at the same location. The other two mark the first sunrise of the winter solstice and of the summer solstice. The purpose of the other posts is not yet known.



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Cahokia Mounds State Historic Site


Greeting the rising sun

A Cahokia market

Community activities

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Middle three paintings: Cahokia Mounds State Historic Site/Michael Hampshire


Artist’s conception of Cahokia as it may have appeared about 1200 C.E. At its height, the city had approximately 20,000 residents

1. Monks Mound

2. Central plaza

3. Twin Mounds

4. Stockade wall

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Cahokia Mounds State Historic Site/William R. Iseminger

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Enlarged Area

Illinois River

Mississippi River

Missouri River

St. Louis

Cahokia Mounds

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Mountain High Maps® Copyright © 1997 Digital Wisdom, Inc.

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The Cahokia Birdman Tablet

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Linear ridgetop mound

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Conical mound

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Platform mound

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Cahokia Mounds Interpretive Center

Monks Mound

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Pictures above and below: Cahokia Mounds State Historic Site

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All photos: Cahokia Mounds State Historic Site