The Octagon Earthworks near Newark, Ohio, align with an 18.6‑year lunar cycle that shifts where the Moon rises along the horizon. Early archaeoastronomy work by Ray Hively and Robert Horn, and later local studies promoted by Brad Lepper, revealed those alignments. Peaks around 2004 and 2006 and a minimum in 2015 illustrate the cycle; the most recent maximum occurred in March 2025. Public moonrise events draw hundreds and emphasize stewardship and teaching in partnership with descendants of the site builders.
Watching the Moonrise: The 18.6‑Year Cycle at Licking County’s Octagon Earthworks
The Octagon Earthworks near Newark, Ohio, align with an 18.6‑year lunar cycle that shifts where the Moon rises along the horizon. Early archaeoastronomy work by Ray Hively and Robert Horn, and later local studies promoted by Brad Lepper, revealed those alignments. Peaks around 2004 and 2006 and a minimum in 2015 illustrate the cycle; the most recent maximum occurred in March 2025. Public moonrise events draw hundreds and emphasize stewardship and teaching in partnership with descendants of the site builders.
06:57 PM, 11/20/2025Culture
This winter marks the close of a lunar northern maximum — part of an 18.6‑year astronomical cycle created by the Moon’s tilted, slightly irregular orbit. At the Octagon Earthworks near Newark, Ohio, that long, slow swing determines where the Moon rises along the horizon and can line up with the site’s carefully laid sightlines.
Archaeoastronomy and local observers
Early surveys by professors Ray Hively and Robert Horn in the early 1980s identified the Octagon’s relationship to this lunar cycle, sparking modern interest in the site’s astronomical purpose. In 1990, site archaeologist Brad Lepper introduced me to their work. When we applied the 18.6‑year cycle to local sightlines, we realized we had just missed a peak and resolved to watch the next swing.
We tracked the cycle through the early 2000s — noting a return to near‑maximum alignment around 2004, a crest in 2006, and a narrowing toward a minimum range by the fall of 2015. The most recent maximum occurred in March 2025, and even when the Moon doesn’t rise exactly on the Octagon’s central axis, it often comes within a full Moon’s diameter or two — close enough to make public viewings compelling.
Community gatherings and stewardship
Public moonrise events at the Octagon routinely reach capacity. Attendance limits protect both visitors (after dark) and the earthworks themselves. Last fall and again this year, hundreds gathered to watch; by year’s end roughly a thousand people will have witnessed the moonrise guided by the site’s historic sightlines.
The Octagon can feel like a vast horizontal clock. The line between an observer — whether standing on the enclosure’s central axis or, perhaps originally, atop the Observatory Mound to the southwest — and the Moon’s rise point acts like a pendulum that swings over decades rather than seconds. Imagine a flat clock face that measures 18.6 years instead of hours.
Purpose and passing knowledge forward
My wish is to see this immense, silent calendar turn again, but I am equally committed to teaching its story now — sharing what we know and the questions that remain in active partnership with the descendants of the builders. Together, we aim to steward the earthworks and pass understanding to future generations — perhaps precisely the purpose for which these enclosures were constructed.
Jeff Gill is a writer, storyteller and preacher in central Ohio. He’s spent nights at the Octagon when nothing was visible, and says that’s part of the experience. Contact: atknapsack77@gmail.com — follow @Knapsack77 on Threads or Bluesky.