Cahokia

The Cahokia Mounds, often simply called Cahokia, is the site of a large Native American city that thrived many years ago, from about 1050 to 1350 CE. It sat right across the Mississippi River from where the city of St. Louis stands today, in southwestern Illinois. This amazing place covers a huge area—about 2,200 acres or 3.5 square miles—and includes around 80 manmade mounds, though the ancient city was actually much bigger than that.

At its peak around the year 1100 CE, Cahokia was a bustling city covering roughly 6 square miles. It had about 120 earthworks of many different shapes and sizes and was home to somewhere between 15,000 and 20,000 people. Cahokia was the largest and most important urban center of what is called the Mississippian culture, a group of advanced societies that lived across much of the Central and Southeastern United States starting around the year 1000 CE.

Today, the Cahokia Mounds are recognized as very important. They are the largest and most complex archaeological site found north of the big ancient cities in pre-Columbian Mexico. The area is protected as a National Historic Landmark and is one of the UNESCO World Heritage Sites within the United States. People can visit Cahokia Mounds, which is open to the public and cared for by the Illinois Historic Preservation Division. It’s a wonderful place to learn about the impressive civilizations that lived there long ago.

History

Historical overview

A map showing approximate areas of various Mississippian and related cultures. Cahokia is located near the center of this map in the upper part of the Middle Mississippi area.

Cahokia was a large city built by Native American people around 600 CE. It grew into the most important center for the Mississippian culture, which spread along rivers across what is now the Midwest, Eastern, and Southeastern United States. Cahokia was located near where the Mississippi, Missouri, and Illinois Rivers meet, making it a great place for trade. People there traded items like copper, shell tools, and shark teeth with communities far away, from the Great Lakes to the Gulf Coast.

Development (9th and 10th centuries

Before the year 1000 CE, people in the area lived in small villages that were used for only a few years. By the end of the 900s CE, these villages grew larger and were built in special ways that followed religious ideas. People started farming more, growing crops like maize, which became important later on.

Rise and peak (11th and 12th centuries

Around 1050 CE, Cahokia grew very quickly. The city had large ceremonial mounds and plazas, and thousands of people lived there. It became the largest city north of Mexico, with a population that may have reached 40,000 at its peak. People from many places moved to Cahokia, bringing new ideas and traditions. The city was a center for religion and trade, with strong connections to other regions.

Decline (13th and 14th centuries

Mississippian period showing the multiple layers of mound construction, mound structures such as temples or mortuaries, ramps with log stairs, and prior structures under later layers, multiple terraces, and intrusive burials

By the end of the 12th century, Cahokia began to decline. Many people left the city, and by 1350 CE, it was abandoned. Scholars think that problems like drought, flooding, and difficulties in getting enough food may have caused the decline. There were also changes in how people lived and believed, which might have made it hard to keep the city together.

Abandonment and resettling (15th through 19th centuries

After Cahokia was abandoned, the area was largely empty until the 17th century when new groups of people moved in. The mounds built by Cahokia’s people were still there, and later settlers, including French colonists, noticed them. As the city of St. Louis grew, many of these mounds were destroyed. Over time, people began to study the site to learn about its history.


Table	900–1050 CE	1050–1100 CE	1100–1200 CE	1200–1300 CE	1300–1600 CE
Archaeological Chronology	Terminal Late Woodland Period	Lohmann Phase	Stirling Phase	Moorehead Phase	Sand Prairie Phase
Developments	Villages nucleate and grow in size. Eastern Agricultural Crops cultivated. Maize introduced.	Urbanization and non-local contacts increase. Religious rituals and administrative centers appear. Greater Cahokia precincts and upland villages in the Richland Complex settled.	Moundbuilding continues. As does religious administration in the hinterlands. A large conflagration in the East St. Louis precinct circa 1160–1170 CE marks the beginning of depopulation.	Upland villages are depopulated. The entire city's population contracts. Storage pits moved inside residences. Marked change in ceramic styles. Non-local contacts are maintained.	Population continues to decline. The city is abandoned by 1400 CE with brief Oneota reoccupation.
Architectural record	Earliest earthen platforms. Villages organized around central feature as cosmograms.	Woodhenge, T-and-L-shaped structures, large circular and rectangular platform mounds, plazas, and causeways.	Continued construction of mounds. The first iteration of the central palisade is constructed circa 1175 CE.	Select mound construction. Termination of certain structures. Large rotundas and T-and-L-shaped structures are no longer constructed. The palisade is rebuilt.	Any possible small-scale mound construction ceases before 1400 CE.

Contemporary usage (post 19th-century)

Museum and Interpretive Center

Cahokia is very important to many Native American peoples today. Tribes such as the Osage Nation, Cherokee, Choctaw, Chickasaw, and Muscogee-Creek honor the site and keep traditions alive, such as mound building. Many visit Cahokia for ceremonies and dances, and it inspires art and literature.

The Cahokia Museum and Interpretive Center welcomes up to a million visitors each year. Cahokia is also important for learning and research. Universities have studied the site since the 1960s. It was named a National Historic Landmark in 1964 and a World Heritage Site by UNESCO in 1982, which helps protect it and brings more support for studies.

Agriculture

Cahokia was surrounded by rich lands where people grew many types of food. Though maize was an important crop, recent studies show that Cahokians ate a variety of foods. Crops like goosefoot and sumpweed from the Eastern Agricultural Complex were also part of their diet. Some people in the city ate less maize, possibly because they were from communities that had not yet made maize a main food.

Researchers debate how Cahokia’s farming affected the land and the city’s eventual decline. Some think the soil may have become too poor, but others argue that the farming methods used by Cahokians were gentle on the soil and may have kept it healthy for a long time. The city thrived during a warm period called the Medieval Warming Period, when crops like maize, beans, and squash grew well. Later, cooler times known as the Little Ice Age coincided with the city’s decline, though these crops continued to be important across North America.

Notable features

The Cahokia Mounds were once a large city of the Native American people, located across the Mississippi River from present-day St. Louis. The original site had 120 earthen mounds spread over 6 square miles, though only 80 remain today. Thousands of workers moved an estimated 55 million cubic feet of earth to build this network of mounds and community plazas.

Monks Mound, the largest structure, covers 14 acres, rises 100 feet high, and was topped by a massive building. The city had a well-planned urban layout with plazas and a ceremonial pathway called the Rattlesnake Causeway. The central district was protected by a wooden fence with defensive towers. Beyond the main area, up to 120 more mounds were spread out, each serving different purposes. The city’s neighborhoods were arranged around plazas, with buildings made from poles and thatch. Researchers also discovered a copper workshop and a series of large timber circles known as Cahokia Woodhenge, used for observing important dates in the year.

Artist's recreation of central Cahokia. Cahokia's east–west baseline transects the Woodhenge, Monk's Mound, and several other large mounds.

Main article: Monks Mound

Main article: Mound 72

Main article: Mound 34

Greater Cahokia

Cahokia was one of the important centers of a large group of related sites. These sites included places like East St. Louis, St. Louis Mounds, Janey B. Goode, and the Mitchell site. Together, these locations are called "Greater Cahokia" because they were all connected and worked together.

Related mounds

Until the 19th century, many mounds like those at Cahokia existed in what is now St. Louis. Most were torn down to make way for buildings, but a few remain. One example is Sugarloaf Mound, which once marked the boundary between St. Louis and Carondelet. Another small mound can still be seen in O'Fallon Park.

One of the largest Mississippian sites is Kincaid Mounds State Historic Site, located in southern Illinois near the Ohio River. This site has 19 mounds and is thought to have been an important place for leaders of the time. It is recognized as a National Historic Landmark.