What if I told you that right here in America—not in Egypt, not in Mexico, but in the cornfields of Illinois and Ohio and Louisiana—there once stood pyramids that rivaled the great monuments of the ancient world?
What if I told you that a thousand years ago, a city on the Mississippi River was larger than London?
And what if I told you that for centuries, white Americans refused to believe that Native Americans built them?
This is the story of the Mound Builders. A 5,000-year tradition of earth-moving, city-building, and spiritual engineering that stretched from the Great Lakes to the Gulf of Mexico. They built tens of thousands of earthen mounds across the eastern half of North America. Some were burial chambers. Some were temple platforms. Some were astronomical observatories. And some were shaped like giant snakes slithering across the landscape.
For the people who built them, these mounds were not just piles of dirt. They were portals—places where the living could communicate with the dead, where priests could commune with the sun, and where the spirits of ancestors could be honored for generations.
And yet, most Americans have never heard of them.
Let me fix that.
Part 1: The Myth That Refused to Die
Before I tell you about the mounds themselves, I need to tell you about the most persistent and racist myth in American archaeology.
When European settlers and explorers first encountered the great earthen monuments of the Mississippi and Ohio valleys, they simply could not believe that Native Americans had built them.
The logic, such as it was, went like this:
Native Americans, the thinking went, were “savages.” Savages could not build cities. Therefore, someone else must have built the mounds.
Who, then?
The theories were creative, to say the least.
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The Lost Tribes of Israel. Some argued that the mounds were built by one of the Ten Lost Tribes of Israel, who had wandered to America after the Assyrian conquest.
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The Toltecs. Others suggested that the Toltecs of Mexico—a “more advanced” civilization—had migrated north and built the mounds.
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The Welsh. No, seriously. A popular theory claimed that a Welsh prince named Madoc had discovered America in 1170 CE and that his descendants built the mounds.
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The Atlanteans. Of course. Whenever there’s an ancient mystery, Atlantis isn’t far behind.
The U.S. government even funded research to prove these theories. The most famous early survey was Ancient Monuments of the Mississippi Valley, published in 1848 by the Smithsonian Institution. Squier and Davis mapped hundreds of sites, producing sketches and descriptions that are still used by archaeologists today—many of the mounds they documented have since been destroyed by farming and development.
Even President Thomas Jefferson got involved. He excavated a mound on his Virginia property, digging a trench through it to see what was inside. It’s considered one of the first scientific archaeological excavations in American history.
But the myth persisted. Even into the 20th century, some textbooks still taught that a mysterious “lost race” of Mound Builders had preceded Native Americans—and had somehow vanished.
They hadn’t vanished. They were still there. The ancestors of today’s Indigenous peoples were the Mound Builders. The only thing that had vanished was the willingness to see them.
Let me give you the proof.
Part 2: The First Mounds – Older Than the Pyramids
Here’s a fact that still surprises most people: the oldest mounds in North America are older than the pyramids of Egypt.
We used to think that Poverty Point in Louisiana—built around 1700 BCE—was the earliest mound complex. Then, in the 1980s, archaeologists discovered Watson Brake, also in Louisiana.
Watson Brake was built around 3500 BCE. That’s over 5,400 years ago. To put that in perspective, the Great Pyramid of Giza was built around 2560 BCE—nearly a thousand years later.
Watson Brake consists of 11 mounds connected by ridges, forming an oval nearly 900 feet across. The mounds range from 3 to 25 feet tall. What’s even more remarkable is who built them: hunter-gatherers.
That blew away everything archaeologists thought they knew. Conventional wisdom had held that only settled agricultural societies could organize the labor needed for monumental construction. But the people of Watson Brake had no agriculture. No pottery. They lived on fish, deer, and wild plants.
And yet, over a 500-year period, successive generations returned to the same spot and built these mounds. Why? We don’t know. Archaeologist Joe Saunders says the mounds “appear to have been raised for their own sake”. They weren’t used for burials, religious rituals, or residences. The purpose remains a mystery.
Then came Poverty Point.
Built between 1700 and 1100 BCE, Poverty Point is one of the most striking archaeological sites in North America. It features six concentric C-shaped ridges facing a central plaza, covering more than a square mile. Three mounds are part of the main complex, including Mound A, which rises 72 feet high and measures 705 by 660 feet at its base.
Here’s what amazes me about Poverty Point: the people who built it engaged in long-distance trade. They imported stone from the Tennessee River Valley and copper from the Great Lakes region—hundreds of miles away. They produced goods on-site and traded them across a vast network.
The design of Poverty Point suggests a belief in sacred geometry. The concentric ridges form a C-shape (some archaeologists believe they once formed a complete circle, later eroded by the river), while the outer mounds are arranged to suggest a square. The entire complex seems designed to focus spiritual energy toward the central plaza, where rituals, games, and ceremonies took place.
Poverty Point was designated a UNESCO World Heritage Site in 2014. It’s a place every American should visit—if only to understand how wrong our history books have been.
Part 3: The Adena – Builders of the Conical Mounds
Around 1000 BCE, a new mound-building tradition emerged in the Ohio River Valley. Archaeologists call them the Adena culture.
The Adena are best known for their conical burial mounds—the classic “mound” shape that most people picture when they think of Mound Builders. These mounds were built over log tombs, where elite individuals were buried with grave goods: copper bracelets, stone tools, shell beads, and ceremonial objects.
The Grave Creek Mound in Moundsville, West Virginia, is the largest conical burial mound in the United States: 69 feet high and 295 feet in diameter.
The Miamisburg Mound in Ohio is even taller: 88 feet high. Today, it sits in a city park, and you can climb stone steps to the top.
But the Adena didn’t just build mounds. They built ceremonial enclosures—circles and squares outlined by earthen walls. These enclosures were often paired with burial mounds, suggesting a complex ritual landscape.
The Adena culture flourished from about 500 BCE to 100 CE. Their influence extended across Ohio, Indiana, West Virginia, Kentucky, and parts of Pennsylvania and New York.
And then, around the time of Christ, something changed. A new culture emerged—one that would take mound building to an entirely new level.
Part 4: The Hopewell – Mathematicians and Astronomers
If the Adena were the pioneers, the Hopewell culture were the masters.
From about 100 BCE to 500 CE, the Hopewell built geometric earthworks of astonishing precision across southern Ohio. Circles, squares, octagons, and parallel lines—laid out over hundreds of acres with a standard unit of measure.
Let me say that again: a standard unit of measure.
When Ephraim Squier and Edwin Davis mapped five Hopewell earthworks in the 1840s, they discovered that each square enclosure was exactly the same size: 1,080 feet to a side, 27 acres. That suggests that the Hopewell had a common unit of measurement—and a sophisticated understanding of geometry—2,000 years ago.
The Seip Earthworks in Ohio is one of the most magnificent examples. It featured over two miles of embankment walls enclosing 89 acres. A large circular enclosure was 1,620 feet in diameter. A smaller circle, 948 feet in diameter, was attached on the west. And a precise square, 1,079 feet on each side, was attached on the southeast.
At the center of the great circle stood the Seip Mound—the third largest Hopewell burial mound ever built: 240 feet long, 160 feet wide, and 30 feet high. Excavations in the 1920s uncovered the famous clay “Seip Head” (now on display at the Ohio History Center) and, preserved by copper salts, fragments of Hopewell cloth woven from milkweed fibers and dyed in intricate patterns.
But the Hopewell also built hilltop enclosures. The Spruce Hill Earthworks, for example, sits on a mesa-like hilltop rising 400 feet above Paint Creek in southern Ohio. A low stone wall—unusual, because most Hopewell walls are earthen—runs just below the brow of the hill, enclosing nearly 150 acres. When non-Native settlers first encountered these hilltop enclosures in the 1800s, they assumed they were “fortifications”—citadels built for defense. But more recent archaeological evidence suggests they were ceremonial centers, just like the geometric enclosures in the valleys below.
Why did the Hopewell build these massive structures? We don’t fully know. There is no evidence that people lived within these earthworks. Rather, they seem to have been designed for large ritual gatherings—pilgrimage sites where celebrants from far away gathered at times determined by astronomical cycles.
The Hopewell traded across an astonishing network. Copper from Lake Superior. Mica from the Appalachians. Obsidian from Yellowstone. Shells from the Gulf of Mexico. This was a continent-spanning system of exchange, all organized by people with no writing, no wheels, and no pack animals.
And then, around 500 CE, the Hopewell culture declined. The reasons are debated: climate change, resource depletion, internal conflict. But the mound-building tradition did not die. It simply shifted south.
Part 5: The Mississippians – America’s First City
Around 800 CE, a new center of power emerged along the Mississippi River. By 1050 CE, it had become the largest city north of Mexico.
Cahokia is the name we give it—though we don’t know what its inhabitants called it.
Cahokia was a planned city. At its peak around 1150 CE, it covered more than five square miles and had a population estimated at 10,000 to 30,000 people. That made it larger than London at the same time.
The center of Cahokia was a diamond-shaped metropolis ringed by a two-mile-long wooden stockade with watchtowers. Inside this palisaded elite quarter stood the great plaza, where ceremonies, games, and rituals took place.
And rising above it all was Monks Mound.
Monks Mound is the largest prehistoric earthen structure in North America: 100 feet high, covering 16 acres at its base. It’s larger at its base than the Great Pyramid of Giza. It was built in stages over centuries, with workers hauling an estimated 15 million basket-loads of dirt to create it.
The mound was flat-topped, and on top stood a massive building—probably the residence of the paramount chief, the “Great Sun.” From there, he ruled a complex chiefdom that controlled much of the Mississippi Valley.
Cahokia was not just a city. It was the center of the Mississippian culture, which spread across the Eastern United States from about 900 to 1450 CE. Mississippian societies were organized as complex chiefdoms, with kinship determining social relationships traced through the female clan line.
The Mississippian economy was based on maize agriculture. They turned hundreds of fertile acres into farmland, growing corn, squash, pumpkins, and sunflowers. This agricultural surplus supported a class of priests, warriors, and elite rulers.
Mississippian religion was dualistic, dividing the world into upper and lower realms, with the earth and humans in between. The purpose of many ceremonies was to maintain balance between these realms. Serpents and other underworld deities were associated with rain, water, and fertility.
Warfare was also a large part of Mississippian society. The wooden stockade at Cahokia—complete with watchtowers—enclosed about 200 acres of the central city. Images of warriors holding the severed heads of their victims appear in Mississippian art.
Despite their power, the Mississippians had no written language. Their beliefs were preserved in engravings on stone figurines, shells, ceramic designs, and stone tablets—a symbolic language we are still learning to read.
Cahokia declined after 1200 CE and was largely abandoned by 1350 CE. The reasons are debated: climate change (the Little Ice Age made farming unpredictable), deforestation, flooding, and possibly internal rebellion.
But the Mississippian tradition continued in other centers—Moundville in Alabama, Etowah in Georgia, and Spiro Mounds in Oklahoma (which we’ve covered in a previous article).
Part 6: The Last Mound Builders – The Natchez
When Spanish explorer Hernando de Soto traversed the southeastern United States between 1540 and 1542, he encountered living mound-building cultures. He saw people living in fortified towns with lofty mounds and plazas—descendants of the Mississippians.
Near present-day Augusta, Georgia, de Soto met a group ruled by a queen, Cofitachequi. She told him that the mounds within her territory served as the burial places for nobles.
The artist Jacques Le Moyne, who accompanied French settlers to Florida in the 1560s, also noted Native American groups using existing mounds and constructing new ones. He produced a watercolor depicting the burial of a tribal chief—”a great solemnity,” the caption read, “and his great cup from which he was accustomed to drink is placed on a tumulus with many arrows set about it”.
The most detailed accounts come from French explorers who encountered the Natchez people in what is now Mississippi. The Natchez were devout worshippers of the sun. With a population of about 4,000, they occupied at least nine villages, presided over by a paramount chief known as the Great Sun, who wielded absolute power.
The Natchez built temple mounds so the Great Sun could commune with God—the sun. His large residence sat atop the highest mound, from which “every morning, he greeted the rising sun, invoking thanks and blowing tobacco smoke to the four cardinal directions”.
The Natchez preserved the mound-building tradition into the early 18th century.
And then, they vanished.
But they didn’t disappear. They were decimated by disease.
Later explorers, only a few decades after mound-building settlements had been reported, found the regions largely depopulated, the residents gone, and the mounds untended. Since little violent conflict with Europeans had occurred in that area during that period, the most plausible explanation is that infectious diseases from the Old World—smallpox, influenza, measles—had wiped out most of the Native Americans who had comprised the last mound-builder civilizations.
The Mound Builders didn’t vanish. They died. They died in staggering numbers, from diseases they had no immunity against, before most Europeans ever saw them.
And then, the survivors—the Natchez, the Chickasaw, the Choctaw, the Creek—were forcibly removed from their lands.
The mounds remained. But the people who built them were pushed aside, and their story was rewritten by those who could not believe that “savages” had built cities.
Part 7: The Mounds Today
Today, thousands of mounds still exist across the eastern United States. Some are preserved as National Parks. Others sit on private land, slowly being eroded by plows and development.
Cahokia Mounds State Historic Site in Illinois is a UNESCO World Heritage Site. You can climb Monks Mound and look out over the Mississippi floodplain, just as the Great Sun did 900 years ago.
Poverty Point in Louisiana is also a UNESCO World Heritage Site. You can walk the concentric ridges and stand in the 37-acre plaza, imagining the rituals that took place there 3,500 years ago.
Hopewell Culture National Historical Park in Ohio preserves several geometric earthworks, including the Seip Earthworks. The National Park Service now mows the outlines of the enclosures, making their huge geometric perimeters visible again.
Serpent Mound in Ohio is the most famous effigy mound in North America—a 1,330-foot-long, 3-foot-high snake slithering across a ridge top. Who built it and why remains a mystery.
And countless other mounds—conical, platform, ridge-top, effigy—dot the landscape from Florida to Wisconsin.
Conclusion: The Earth Still Remembers
Here’s what I want you to take away from this.
For 5,000 years—longer than the pyramids of Egypt have stood—the Indigenous peoples of North America built earthen monuments across the eastern half of the continent. They built cities that rivaled anything in Europe. They built geometric earthworks that required advanced mathematics and astronomy. They built a continent-spanning trade network that moved copper from Lake Superior to the Gulf of Mexico.
And then, in the space of a few generations, most of them died. Not in battle. Not in a great catastrophe. But from diseases brought by Europeans—diseases they had no resistance to.
The survivors were pushed west. The mounds were plowed under, built over, or simply forgotten. And a myth arose—convenient, self-serving, and deeply racist—that the Mound Builders were a “lost race” who had vanished before Native Americans arrived.
That myth was a lie.
The Mound Builders were Native Americans. Their descendants are still here. And the mounds they built are still standing—silent witnesses to a history that most Americans have never been taught.
The next time you drive through Ohio or Illinois or Louisiana, look for the signs. Park the car. Climb the mound. Stand where the Great Sun stood, greet the rising sun, and remember.
The earth still remembers what we have forgotten.
