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117 parks in 7 regions

Great Serpent Mound

Peebles · Adams County · Southern Ohio

The largest serpent effigy in the world

National Historic LandmarkUS World Heritage tentative listEffigy mound

Visiting information you can trust

Content last reviewed: September 2026 — this is when Field Notes Ohio's content was last checked, not a live status.
Primary official source: Official page
Location confidence: Verified property location
Located from the site's street address
Check current conditions: Official conditions or closures
Reservations or tickets: Tickets or admission info

Prices, hours, closures, campsite availability and trail conditions shown elsewhere on this page are not live — always confirm with the official source before you go.

A gigantic earthen snake on a hilltop over Ohio Brush Creek, built by a people whose name is still argued over.

Shape: A serpent with a curled tail, its open mouth nearly swallowing an oval
Length: About 1,348 feet (some sources say 1,330), roughly 3 to 4 feet high
Age: Debated: about 300 BCE (Adena) by newer dating, about 1070 CE (Fort Ancient) by 1990s dating
Setting: A plateau above Ohio Brush Creek, on the rim of the ancient Serpent Mound crater
Managed by: Ohio History Connection, with the Arc of Appalachia
Designations: National Historic Landmark and National Register of Historic Places (1966); on the U.S. tentative list for World Heritage status

The story

Serpent Mound is a sculpture in earth: a snake about 1,348 feet long, coiled and uncoiling along a ridge, with its jaws open around an oval hollow. It sits on a plateau above Ohio Brush Creek in Adams County, on the edge of what geologists call the Serpent Mound crater, the eroded remains of an ancient meteorite or asteroid impact from roughly 300 million years ago. Ephraim Squier and Edwin Davis surveyed it for the Smithsonian's first publication in 1848, and Harvard archaeologist Frederic Ward Putnam excavated it in the late 1800s. In 1908 a 25-foot observation tower went up near the serpent's tail.

Nobody has been able to say for certain who built it. The mound holds no burials and no artifacts that tie it to one culture, though three burial mounds stand nearby, two Adena and one Fort Ancient. Putnam's charcoal dated it to about 300 BCE and pointed to the Adena. Radiocarbon work in the 1990s pointed to about 1070 CE and the Fort Ancient people, and a 2014 study returned to about 300 BCE. Some researchers now suggest the Adena built it and Fort Ancient people refurbished it centuries later.

The head aligns with the summer solstice sunset, and the coils may point to the winter solstice and the equinox sunrise. One theory ties its building to the light of a supernova. It is on the U.S. tentative list for World Heritage status.

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The Serpent, the Egg and the Frog

For nearly two centuries people have argued about what the serpent is doing. Squier and Davis saw a snake swallowing an egg, and that picture stuck. Others said the oval is the sun, or the moon, or a frog, and one archaeologist read the whole thing as the body of a frog instead of a snake. One popular explanation is that the builders chose the crater's rim because the ground was strange, and that the head points to the summer solstice sunset.

The mound also has a rescue story. In the 1800s the earthwork was neglected, and Harvard's Putnam and a group of Boston women raised money to buy the land and preserve it.

Behind the legend

The dating fight is real and unresolved. Radiocarbon dates from the 1990s put the mound at about 1070 CE, and a 2014 study put its primary construction at about 300 BCE, with the later date as a refurbishment. The impact crater is real too, and the mound was built on its rim, but scientists have no evidence that the builders knew that. The alignments are suggestive, not proven.

What is solid is the site's standing. It became a National Historic Landmark in 1966, and in 2008 the U.S. Department of the Interior put it, with eight other Ohio earthworks, on the tentative list for World Heritage status.

If you go

Walk the paved path around the whole serpent and stand at its head at sunset if you can, since the head aligns with the summer solstice sunset. Take the archaeology tour on a second or fourth Friday for the best explanation. Then visit Fort Hill about 16 miles north.

Visiting

Status

Open Tuesday to Sunday

Managed by

Ohio History Connection

Hours

Closed Mondays. Tuesday to Saturday 10 a.m. to 5 p.m., Sunday noon to 5 p.m. Final entry at 4 p.m.; the site closes at 5 p.m. Museum and grounds may close in bad weather.

Admission

Parking is $8 per car (Ohio History Connection members free). Guided archaeology tours run on the 2nd and 4th Fridays at 1:30 p.m. during the season.

Phone

800-752-2757

Please note

Stay on the paved path and do not walk on the earthworks. Serpent Mound and the three nearby burial mounds are sacred to many people today. Visitors have reported the observation tower closed for maintenance, so check ahead.

Address

3850 State Route 73, Peebles, OH 45660

Official information →Directions