Step back nearly a thousand years, to a time before skyscrapers, highways, or the sprawl of St. Louis. Across the Mississippi River, an Indigenous metropolis rose from the fertile floodplains. It was bigger than London in its day, teeming with people, culture, trade, and innovation. This was Cahokia, a city of earth and vision, where people built monumental mounds, charted the skies, and forged connections stretching across the continent.
Today, Cahokia Mounds State Historic Site preserves the remnants of this extraordinary city. Recognized as both a US National Historic Landmark and a UNESCO World Heritage Site, it stands as one of the most important archaeological treasures in North America.
A City Ahead of Its Time
Cahokia wasn’t just a cluster of villages. Around 1100 CE, it flourished as the largest city of the Mississippian culture, covering more than 4,000 acres. Scholars estimate its population ranged from 15,000 to 20,000 people, making it one of the largest urban centers in the world at the time. To put that in perspective, Cahokia was larger than many European cities of the same period.
What made it unique was its organization. This was a planned city, complete with residential neighborhoods, ceremonial plazas, and monumental earthworks. It reveals that Indigenous societies in North America built complex urban environments long before European contact.
The Mounds That Defined a Civilization
When you walk the site today, the most striking features are the earthen mounds that rise from the Illinois prairie. Archaeologists believe Cahokia once contained about 120 mounds of varying shapes and purposes. Roughly 80 survive within the protected state park boundaries.
- Monks Mound: The largest mound at Cahokia, standing about 100 feet tall and covering more than 14 acres at its base. It is the biggest pre-Columbian earthen construction north of Mexico. Researchers think it supported a massive building at the top, likely a political or ceremonial center.
- Platform Mounds: These flat-topped mounds supported homes of elites, temples, or council houses.
- Conical Mounds: Typically used for burials.
- Ridgetop Mounds: Their purpose remains debated, but they may have served as territorial markers or memorials.
Walking the trails, you can still feel the scale of these structures, built entirely by human labor with baskets of earth carried one load at a time.
Woodhenge: An Ancient Calendar
One of Cahokia’s most fascinating discoveries is Woodhenge, a series of large timber circles that once stood just west of Monks Mound. Like England’s Stonehenge, these alignments tracked the sun’s movements throughout the year…