A City Built from Earth
Near modern East St. Louis, Illinois, the Mississippian city of Cahokia rose beside the Mississippi River. At its peak between the 12th and 13th centuries, it may have held more than 20,000 people, making it the most populous city in North America at the time.
Cahokia belonged to a broader culture that spread through the Southeast and Midwest. Its people grew maize intensively, participated in long-distance trade, and organized society into ranked political and religious systems. Large plazas and earthen mounds formed the city’s ceremonial landscape.
Monks Mound
The city’s centerpiece, Monks Mound, remains the largest earthen construction in the prehistoric Americas. Its scale reveals the labor, planning, and authority required to transform soil into monumental architecture. The mound-building tradition was not new: earlier societies had created major works at Watson Brake and Poverty Point. Cahokia developed that tradition into an urban system.
Trade connected the Mississippian world to the Great Lakes and Gulf of Mexico. Objects and materials could move across enormous distances, linking communities that shared neither a single ruler nor a uniform way of life.
Collapse and Catastrophe
Cahokia and related societies declined before Europeans arrived. When Hernando de Soto’s expedition crossed the Southeast in the 1540s, encounters brought disastrous consequences. European diseases devastated Indigenous populations and disrupted social structures. By the time Europeans returned about a century later, many Mississippian groups had disappeared and large areas were sparsely inhabited.
Cahokia’s mounds offer a powerful correction to old assumptions about North American history. They mark the remains of a major urban civilization—one whose city was built not from stone, but from earth.