Illinois: Cahokia Summary

  • Last updated on November 10, 2022

The Cahokia Mounds were built by Mississippian Indians, who used the mounds as ceremonial centers. The largest and most famous of these structures is Monks Mound, which rises to a height of one hundred feet and has a base measuring eight thousand square feet. Sixty-eight of the estimated one hundred twenty mounds can still be viewed. The nearby town of Cahokia was founded in 1699 by French missionaries. It is the oldest permanent European settlement in Illinois and contains many historic French colonial buildings.

Site Offices:

Cahokia State Historic and World Heritage Site

P.O. Box 681

Collinsville, IL 62234

ph.: (618) 346-5160

Cahokia Chamber of Commerce

905 Falling Springs Road

Cahokia, IL 62206

ph.: (618) 332-1900

In southern Illinois, about fifteen miles east of St. Louis, Missouri, lie the Cahokia Mounds, the remains of what was once the largest prehistoric American city north of Mexico. Some authorities estimate that its population reached 20,000, although other scholars believe the population may have grown as large as 100,000. The people of ancient Cahokia, who are today referred to as Mississippians, were strong, successful, and peaceful. Their culture emerged between 850 and 900 c.e., out of an earlier, late Woodland culture that developed there around 500 c.e. The Mississippians are remembered most for the amazing ceremonial mounds they built, many of which still exist. Because their population had vanished long before Christopher Columbus found his way to America in 1492, their history at Cahokia was unknown until relatively recently.

Early Mound Builders

Cahokia’s ceremonial mounds at one time numbered one hundred twenty and covered thousands of acres. They were built between 900 and 1300 c.e., along the Mississippi River. Today, the sixty-eight remaining mounds, which span an area of 2,200 acres, are preserved in an archaeological park. The remains of thousands of other mounds have been found nearby in Illinois.

It is said that early white settlers refused to farm near the mounds because they were afraid of disturbing an Indian god. Eventually, the settlers simply worked around the mounds, paying little attention to them until the late 1800’s. Although many mounds have been carefully preserved, others are now located in the midst of local farms.

The site’s earliest history was not even known until the early 1800’s. The pioneers who came upon the mounds at first would not believe they were built by Indians. They thought instead that Vikings, Phoenicians, or a lost tribe of Israel had built them. By the 1890’s, people finally agreed that early Native Americans had indeed built the mounds.

Monks Mound

By far the most impressive mound is Monks Mound, or the Great Cahokia Mound. With a base measuring one thousand feet by eight hundred feet–broader than the Great Pyramid of Cheops in Egypt–and a height of one hundred feet, it is the largest prehistoric earthen structure in the New World. More than twenty-two million cubic feet of earth was moved just to build Monks Mound, a pyramidal structure with straight sides, almost in the shape of a parallelogram. On its south side, about thirty feet above the base, is a large terrace, which is now home to an orchard. On the other side, about sixty feet from the base, is a smaller, forested terrace. Atop the mound was a huge wooden palace, which measured 105 feet long by 48 feet wide by 50 feet high. According to one expert, construction of Monks Mound required the labor of thousands of Indians and was built in several stages. Named for Trappist missionaries who planted a garden there from 1809 to 1813, Monks Mound was originally home to the Mississippians’ high chief, who lived on its flattened peak in the palace.

Smaller platform mounds were home to ceremonial buildings and the elite members of the population. The Mississippians also constructed conical and ridge-top mounds, which marked key locations and served as burial sites for the elite members of the population. In one smaller ridge-top mound known as Mound Seventy-two, archaeologists found a chief laid on a bed of twenty thousand shell beads, surrounded by copper, mica, arrowheads, and the remains of several people sacrificed to serve him in the next life. The victims included fifty-three young women, as well as four men with their heads and hands removed. The mound revealed more than two hundred other ceremonial and sacrificial burials, mostly of young women, in mass graves. Despite these findings, scholars believe that most Cahokians were buried in cemeteries.

Architectural Features

The mounds were arranged in neat rows around a ceremonial plaza that featured stepped pyramid temples. Stone, shell, and wood tools were used to dig out the claylike earth that built the mounds. The Mississippians then carried this material in baskets on their backs. Other mounds included “wattle-and-daub” houses for the less elite members of the area. These structures were built from woven reed walls covered with mud plaster and were arranged in rows around central plazas. A fifteen-foot stockade encircled the city. There were also four or five large woodhenges, or circles of cedar posts spaced at twenty-foot intervals. These woodhenges, names for their similarity to England’s Stonehenge, are thought to have been horizon calendars, which used shadows to mark the changing seasons and ceremonial periods. They were probably built around 1000 c.e.

Disappearance of the Mound Builders

Because the mound builders left no written language, there is much about them that may never be known. It is known, however, that at their peak around 1000 c.e., they were peacefully developing their own government, public works projects, science, art, and specialized labor force. Although the area was named by French missionaries for the Cahokia, a subtribe of the Illini, who lived near the mounds in the seventeenth century, its original population vanished between 1300 and 1500. By the standards of the time, the people of the area were very wealthy. Their success came in part from an abundant supply of corn, sunflowers, and squash. Their location along the Mississippi River also allowed them to create a vast trading network that reached as far south as the Gulf of Mexico and as far north as the Great Lakes.

Theories for the demise of the community vary. Some believe that the mound builders fell victim to war, disease, or a depletion of resources. The inhabitants might have become too reliant on lumber for fuel and building materials, causing them to remove too many trees from bluffs in the area. This would have allowed heavy rainfalls to wash over the soil and wipe out the crops. Other scholars claim that the cornfields gradually lost their fertility from overuse.

Later Inhabitants of the Region

Tamaroa Indians later inhabited the area, and European traders, merchants, and explorers soon visited it. In 1698 the French explorer Henry de Tonti led a group of missionaries to the region; in 1699 they returned to establish a mission there, just fifteen miles to the southwest of the mound site. It was the first permanent European settlement in what would become the state of Illinois.

Cahokia’s Mission of the Holy Family was established by priests from Quebec’s Seminary of Foreign Missions; these missionaries soon found themselves in a territorial conflict with Jesuits who were also working in the area. When several Jesuits entered the town and began constructing a Cahokia mission of their own, the Seminary of Foreign Missions sent a representative to France to reaffirm their sole authority there. The resulting June 7, 1701, decree gave them authority over Cahokia, but it gave the Jesuits jurisdiction over the rest of the Mississippi Valley. In 1703, the Jesuits established their own mission at Kaskaskia, sixty miles below Cahokia. Relations between the two towns would remain strained for more than a century.

Cahokia became a center of trade for the flat-bottomed boats that transported goods to and from New Orleans via the Mississippi River. This trade increased markedly in the early decades of the eighteenth century as a result of the “Mississippi Bubble,” an ill-fated investment scheme initiated in 1717 by Scottish financier John Law. Law proposed to settle six thousand colonists and three thousand slaves in France’s Mississippi Valley colonies. Although Law’s Compagnie d’Occident soon went bankrupt, the scheme brought many colonists into the area and increased the demand for goods up and down the Mississippi.

British and American Rule

As a result of the French and Indian War, France ceded its Mississippi Valley colonies to Britain in November, 1762. The British took formal possession of the Cahokia area in 1765, by which point many of the French settlers has moved across the Mississippi to Spanish-controlled Missouri. In 1767, Captain Pittman, who served with the British forces in Illinois, wrote that “the village is long and straggling, about a half mile from north to south, with 45 dwellings.”

In 1778, Virginia troops under Colonel George Rogers Clark gained possession of the area during the American Revolutionary War. The troops stayed until 1780, but, like the British, they had little impact on the town, which remained French in both its population and its character. By 1787, Cahokia’s population had reached four hundred, almost all of whom were French.

The Colonial Legacy

Modern-day visitors to Cahokia can still see this French colonial legacy in the town’s many historic buildings. One of the most famous is the St. Clair County Courthouse. The courthouse was originally built by Jean Roy Lapance as a residence, most probably in the late 1700’s. Eventually, François Saucier married into the Lapance family and became the home’s new owner. In 1793, he sold it to St. Clair County for one thousand dollars. As the oldest courthouse in Illinois, it remains a prime example of the structures built by the early French settlers. It is constructed of vertically arranged logs and is surrounded by extended eaves. Many of the French who came to Illinois were originally from the West Indies and had grown accustomed to using the eaves as protection against the hot sun and rains.

From 1793 until 1814, the building served as both courthouse and military center. Outside were a whipping post, stocks, a pillory, and other devices of punishment. In 1814, St. Clair’s county seat was moved from Cahokia to Clinton Hills, which is now the city of Belleville, and François Vaudry bought the courthouse for $225. Over time the building would serve a variety of uses, including a warehouse, a residence, and even a saloon. Eventually, it was sold for exhibition at the World’s Fair in St. Louis. Following the fair, the building was relocated to Jackson Park in Chicago. In 1939, the state of Illinois had the former courthouse restored and placed on its original site in Cahokia.

The courthouse is one of only a handful of vertical-log French structures still standing in Illinois. Another is the Church of the Holy Family, also located in Cahokia. Built in 1799 on the east side of what is today Illinois Route 3, it is the oldest church in the Mississippi Valley. Another vertical-log building stands just opposite the church; during the 1880’s, it was home to François Saucier.

Another historical colonial building is the Jarrot Mansion, a two-story brick home built by Nicholas Jarrot between 1799 and 1806. In 1790, twenty-six-year-old Nicholas Jarrot came to America from France. He stopped first in Baltimore and New Orleans before settling in Cahokia, where he prospered from a successful trading business. (It was Jarrot who gave the large Cahokia mound to the Trappist order, resulting in the name “Monks Mound.”) His mansion is a large, colonial-style house, thirty-eight by fifty feet, two stories high, with a basement and an attic. The massive structure also features walls ranging from sixteen inches to two feet thick. Many of the materials for the mansion were imported from France. Today, it is the oldest brick building still standing in Illinois. The Jarrots threw lavish parties at the mansion. A visitor during this period commented that so many balls were held there, he “often wondered how the ladies are enabled to support themselves under this violent exercise. . . . ”

Because the house was located on a flood plain, it often took in water when the river was swollen. An earthquake damaged the structure further in the early 1810’s. In recent years, the building has been used as a Catholic parochial school and a home for the nuns who teach there.

The End of Cahokia’s Independence

Cahokia was virtually an independent city-state during the years immediately after the American Revolution. Whereas several of the surrounding towns succumbed to disorder and political corruption during this period, Cahokia, with its deep religious roots, governed itself with restraint and discipline. The difference between Cahokia and its neighbors soon grew to the point that Cahokians wished to remove themselves from the authority of the county government. Their desire was only quickened by the fact the county seat was in Kaskaskia, their longtime rival. In 1786, they officially petitioned the U.S. Congress to remove them from the authority of the Kaskaskians, whom they charged with “incapacity, spite, and partiality.” In 1790, Cahokia was made a joint county seat with Kaskaskia and Prairie du Rocher, and in 1795 it was made sole seat of the newly drawn St. Clair County. As St. Clair County grew, so did Cahokia’s prestige and authority; by 1809, St. Clair included all the territory in what are today the eighty northernmost counties of Illinois.

Cahokia would not enjoy this position of authority for long, however. When the political map was redrawn again in 1814, the seat of St. Clair County was moved to Clinton Hills (preserved Belleville). Furthermore, St. Louis and East St. Louis soon emerged as economic powers; because Cahokia was repeatedly flooded by the waters of the Mississippi, these cities attracted the settlers and businesses that Cahokia needed to grow. By 1914, the town was home to only forty-two dwellings, three less than Captain Pittman had counted in 1767. Descendants of the original French settlers continued to make up a large part of the local population. Thanks to industries that located to the area in the twentieth century, the town’s population rose to approximately seventeen thousand by 1990.

Meanwhile, the nearby mounds had been all but forgotten. Farms, houses, and other buildings appeared on the land that covered the once-majestic structures. While some attempts at investigation and restoration began in the 1920’s, it was not until 1982 that the United Nations Educational, Scientific, and Cultural Organization (UNESCO) named Cahokia one of its World Heritage Sites. Three years later, the state created the Illinois Historic Preservation Agency to protect such cultural sites. Over the course of the 1970’s and 1980’s, the state spent $1.3 million to remove an entire sixty-home subdivision from the site. An $8.2 million interpretive center was completed there in 1989. Despite these efforts, by 1993 less that 1 percent of the area had been excavated.

For Further Information
  • Fowler, Melvin L. The Cahokia Atlas. Springfield: Illinois Historical Preservation Agency, 1989. A detailed, scholarly overview of archaeological knowledge about the mounds.
  • Gums, Bonnie L. Archaeology at French Colonial Cahokia. Springfield: Illinois Historical Preservation Agency, 1988. One of the best and most recent scholarly works on the town of Cahokia.
  • McDermott, John Francis, ed. Old Cahokia: A Narrative and Document Illustrating the First Century of Its History. St. Louis: St. Louis Historical Documents Foundation, 1949. Older, but still valuable.
  • Mink, Claudia G. Cahokia: City of the Sun. Collinsville, Ill.: Cahokia Mounds Museum Society, 1992. Quite informative and written for a general audience.
  • Young, Biloine W. Cahokia, the Great Native American Metropolis. Urbana: University of Illinois Press, 2000. An archaeological description of the mounds and ceramics at Cahokia and of the pre-Columbian history of Mississippian culture.
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