Deep in southern Ohio, a 1,348-foot earthen snake sits on top of a meteor crater

It’s the world’s largest serpent effigy

Deep in Adams County, about 75 miles east of Cincinnati, a quarter-mile-long earthen snake winds across a wooded plateau above Ohio Brush Creek.

The Great Serpent Mound stretches 1,348 feet through seven coils and ends in a triple-coiled tail. Its head opens around a 120-foot oval shape that nobody has figured out yet.

The whole thing stands only three feet high, which means you can walk right past it and barely notice. But from above, the shape hits you all at once, and the story behind it goes back thousands of years.

Two ancient cultures may have built it centuries apart

Who built it depends on who you ask. Radiocarbon testing in the 1990s dated charcoal inside the mound to around 1070 CE, pointing to the Fort Ancient culture.

Then, the 2014 tests pushed the date back to roughly 321 BCE, which lines up with the Adena people. Most archaeologists now think the site mattered to multiple cultures across many centuries.

Harvard archaeologist Frederic Ward Putnam excavated the site in the late 1880s and found no artifacts inside the serpent itself, only in nearby burial mounds.

Putnam saved the site in 1887 for $6,000

Putnam did more than dig. He led the effort to buy the 60-acre site in 1887 through Harvard’s Peabody Museum, turning it into one of the first privately funded archaeological preserves in the country.

Without that purchase, the land could have gone to farming or development. Harvard transferred ownership to Ohio in 1900, and the Ohio History Connection manages it today.

That chain of custody, from a 19th-century Harvard professor to a state agency, kept the mound intact for over a century.

Climb the observation tower to see every coil at once

From the ground, the serpent looks like a low grassy ridge. You can’t read the shape at all.

That changes the moment you climb the observation tower near the center of the site. From the top, every coil snaps into place.

The spiral tail, the winding body, the open-mouthed head, all of it laid out across the hilltop with forested hills and the Brush Creek valley behind it.

There’s no elevator, just steep stairs, but the view makes the climb worth it.

Walk the paved path from tail to head

A paved path circles the entire mound and brings you within a few feet of the earthwork along its full length.

You start near the spiral tail, where the bluff drops steeply toward the Brush Creek cliffs below, and follow the serpent’s winding body past three main coils to the head.

Interpretive panels along the way cover the site’s history and ongoing research.

Go early in the morning or late in the afternoon, when low sun throws long shadows across the grass and the serpent’s shape stands out the sharpest.

The museum fills in what the mound can’t tell you

A small museum near the parking area holds Adena and Fort Ancient artifacts found in the surrounding hills.

You’ll see stone tools, pottery fragments, and dioramas showing how these cultures built their burial mounds and effigy mounds.

A short film gives you the full overview before you walk the site, which helps if you’ve never heard of Ohio’s earthwork traditions. First-time visitors especially benefit from starting here.

A gift shop inside carries books, educational materials and locally made items.

Hike the woodland trail down to Brush Creek

Beyond the paved mound path, the Ohio Brush Creek Hiking Trail drops through dense hardwood forest down the bluff toward the creek valley.

At the bottom, you can look back up at the plateau where the serpent sits and get a completely different sense of the site’s scale.

The forest is oak and hickory, and you might spot deer, wild turkey, or songbirds along the way. The trail has steep sections and cliff edges, so keep children close and stay on the marked path.

The serpent’s head points at the summer solstice sunset

The serpent’s open head aims directly at the spot on the western horizon where the sun sets during the summer solstice. That alignment is well-documented and deliberate.

Some researchers think the body’s coils may also track equinox sunrises and positions in the moon’s 18.6-year cycle, though those connections are still debated.

Every year, the Ohio History Connection hosts a Summer Solstice event with extended hours so you can watch the alignment happen in real time.

It’s one of those things you have to see in person to fully grasp.

You’re standing on a meteor crater eight miles wide

The plateau under your feet is part of the Serpent Mound Impact Structure, a confirmed meteor crater roughly eight miles across.

The Ohio Department of Natural Resources puts the strike between 252 and 330 million years ago. The asteroid shattered bedrock more than a mile deep and shoved rock layers upward by as much as 1,000 feet.

Erosion has worn down the rim over millions of years, but the geology is still visible in exposed rock formations nearby.

The Ohio DNR even publishes a self-guided driving tour of nine spots where you can see the evidence yourself.

Join a 90-minute tour led by a working archaeologist

Twice a month during the open season, archaeologist Bill Kennedy of the Ohio History Connection leads guided walks that start at the museum and run about 90 minutes.

Kennedy covers the pre-contact American Indian cultures in Ohio and goes well beyond what the interpretive panels tell you. Tours fall on the second and fourth Fridays of each month during the 2026 season.

Check the Ohio History Connection’s official website or social media before you go for current schedules and weather-related cancellations.

Two burial mounds bookend the site with 2,000-year-old graves

Two conical burial mounds sit near the parking area at opposite ends of the site, separate from the serpent itself.

The Adena culture built these, and 1880s excavations turned up human remains, stone tools and other artifacts inside.

The larger mound started with the burial of a single prominent individual more than 2,000 years ago, and later generations added burials that grew the mound over time.

Unlike the serpent, which holds no human remains, these mounds served a clear funerary purpose and prove the hilltop carried ceremonial weight long before the effigy took shape.

The Shawnee Tribe came home to the mound in 2021

Serpent Mound still carries weight for modern Native American tribes with roots in the Ohio Valley.

In 2021, members of the Shawnee Tribe visited the site for the first time since the federal government forced their removal from Ohio in the 1830s. The Ohio History Connection extended the invitation.

The Shawnee have a Snake Clan and oral traditions involving serpents that tie their living culture directly to this ancient earthwork.

Since 2020, the Ohio History Connection has conducted community-engaged archaeology here in partnership with tribal communities, making this a place of continuing connection, not just history.

Explore Serpent Mound in Adams County, Ohio

You can find Serpent Mound at 3850 State Route 73 in Peebles, Ohio, about 75 miles east of Cincinnati and 85 miles south of Columbus. The Ohio History Connection manages the site.

Pets are welcome on leash, and there’s a picnic area on the grounds.

Check the official website before you drive out for current hours, seasonal schedules and any event updates. The site sits in one of the most remote stretches of southern Ohio, so plan your fuel stops ahead of time.

This article was created with AI assistance and human editing.

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