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Ohio inventions and firsts · Achievement · c. 300 BCE or c. 1070 CE

Great Serpent Mound

The 1,348-ft effigy mound in Adams County is the largest known serpent effigy; a 2014 radiocarbon study suggested Adena builders about 300 BCE, but Brad Lepper argues Fort Ancient (c. 1070 CE). NHL 1966, Ohio History Connection site.

At a glance

Year
c. 300 BCE or c. 1070 CE
Place
near Peebles, Adams County ZIP 45660 · Adams County

The story

On a ridge above Brush Creek in Adams County, Ohio, near Peebles, lies the largest serpent effigy in the world: a snake shape 1,348 feet long and about four feet high, built of earth. Nobody wrote down who made it or why.

Scholars disagree about the date. A 2014 radiocarbon study suggested it was built about 300 BCE by the Adena culture. Archaeologist Brad Lepper challenged that, arguing from methodology that the Fort Ancient culture built it around 1070 CE.

In the 1880s Frederic Ward Putnam led efforts to restore it, raising money to buy 60 acres. It became the first privately funded archaeological preserve in the United States. Research suggests the oval-to-head area of the serpent lines up with the summer solstice sunset and the coiled tail with the winter solstice sunrise.

Serpent Mound became a National Historic Landmark in 1966 and is managed by the Ohio History Connection.

Timeline

  • 300 BCE?: Possible Adena construction, per the 2014 radiocarbon study. (Adams County, OH) source
  • 1070 CE?: Alternative date, Fort Ancient culture, argued by Brad Lepper. (Adams County, OH) source
  • 1880s: Frederic Ward Putnam raises funds, buys 60 acres, and restores the mound. (Adams County, OH) source
  • 1966: Designated a National Historic Landmark. (Adams County, OH) source
  • 2014: Radiocarbon testing suggests about 300 BCE. (Adams County, OH) source

What it changed

  • The world's largest serpent effigy at 1,348 feet.
  • First privately funded archaeological preserve in the U.S.

Why it matters

Iconic prehistoric earthwork.

Who gets the credit is disputed

The Ohio claim. A 2014 radiocarbon study suggested that Adena builders made the Great Serpent Mound in Adams County about 300 BCE.

The other claims. Archaeologist Brad Lepper argues that it was built by the Fort Ancient people around 1070 CE, so both its age and its builders are disputed.

Places in Ohio to see

Further reading

Sources

Confidence. Medium: the main facts were confirmed, but some details (often an address or ZIP code) were not.