In Newark and Heath, Ohio, on flat ground between a highway and a housing estate, stand the largest earthen enclosures in the world. They were built by the Hopewell culture between 100 BCE and 400 CE: a great circle, an octagon joined to a circle, and a square, spread across what was once about 3,000 acres. Less than ten percent of the complex survives — 206 acres of walls, moats and mounds — but what survives is enough to show that the people who built it were tracking the Moon with a precision that took modern archaeologists by surprise.
In September 2023, the Newark Earthworks were inscribed on the UNESCO World Heritage List, together with the earthworks at Hopewell Culture National Historical Park and Fort Ancient, as the Hopewell Ceremonial Earthworks. It was the first World Heritage Site in Ohio. For most of the previous century, part of it had been a golf course.
A Circle, an Octagon, a Square
The Newark Earthworks consist of three preserved sections: the Great Circle Earthworks, the Octagon Earthworks and the Wright Earthworks. The Great Circle is one of the largest circular earthworks in the Americas. A moat five feet deep is encompassed by walls eight feet high — taller still at the entrance — and at the centre of the circle sits Eagle Mound, named by early settlers who believed its shape resembled an eagle in flight.
The Octagon is the strangest and most precise of the three. It is an eight-sided enclosure joined to a smaller circle, covering roughly fifty acres. In 1982, researchers from Earlham College in Richmond, Indiana, concluded that the complex was a lunar observatory. Scholars have since demonstrated that the Octagon’s alignments track the Moon’s orbit during its 18.6-year cycle — the slow wobble of the Moon’s rising and setting points along the horizon, which returns to the same extremes only once every 18.6 years. To build an observatory for that cycle, the Hopewell had to watch the Moon for at least a generation, and probably several, and then lay out earthworks on a scale of hundreds of metres to mark what they had seen.
The Wright Earthworks, the third section, are the remains of a square enclosure. Together, the three sections are the largest surviving Hopewell earthwork complex in North America.
The Hopewell were not a single tribe but a network of Indigenous cultures across the Eastern Woodlands, linked by trade and ceremony. They built great mounds and earthworks, and they moved materials over astonishing distances: obsidian from Yellowstone, copper from the Great Lakes, marine shells from the Gulf of Mexico, all found in Hopewell sites in Ohio. The Newark Earthworks are the largest thing they built, and the most precise.
The Golf Course
The modern history of the site is almost as strange as the ancient one. The Newark Board of Trade owned the Octagon property until 1918. In 1910, the property was leased to the Moundbuilders Country Club, which developed the site as a golf course. Golfers played through the Octagon for more than a century, putting across ground that had been laid out to track the Moon two thousand years earlier. A Licking County court case led to a trustee being named to manage the property from 1918 to 1933, but the golf course stayed.
The arrangement survived because it was, in an odd way, protective: the club maintained the grounds, and the earthworks were not built over. But it also meant that public access to one of the most important archaeological sites in North America was limited to a few open days a year. The Octagon and Great Circle Earthworks are now managed by the Ohio History Connection, and the long lease has been the subject of legal action to secure full public access.
The World Heritage Listing
The Newark Earthworks were one of fourteen sites nominated in January 2008 by the United States Department of the Interior for potential submission to the UNESCO World Heritage List. The nomination took fifteen years. In September 2023 the site was officially designated a World Heritage Site, together with the Hopewell earthworks at Fort Ancient and Hopewell Culture National Historical Park.
The listing recognises what the Hopewell built and what it means: a ceremonial landscape of a scale and precision unmatched in its time and place, built by a culture that left no written records, and understood today almost entirely through the earthworks themselves. The walls and moats are the documents. The Moon, rising over the Octagon once every 18.6 years, is the text.
What Is Documented, and What Is Not
Documented: The Newark Earthworks in Newark and Heath, Ohio, consist of the Great Circle, the Octagon and the Wright Earthworks, built by the Hopewell culture between 100 BCE and 400 CE. The complex originally covered about 3,000 acres; 206 acres survive, containing the largest earthen enclosures in the world. The Octagon tracks the Moon’s 18.6-year cycle, a conclusion reached by Earlham College researchers in 1982 and confirmed by later scholarship. The Octagon property was leased to the Moundbuilders Country Club as a golf course in 1910. The site was inscribed on the UNESCO World Heritage List in September 2023 as part of the Hopewell Ceremonial Earthworks.
Unverified or disputed: The precise ceremonial purposes of the enclosures beyond the lunar alignments; the exact construction sequence and the labour organisation behind it; how the Hopewell measured and laid out the 18.6-year cycle. The claim that Eagle Mound resembles an eagle in flight is an early settlers’ interpretation, not a documented Hopewell intention.