There are mounds in Ohio created by native peoples that are thousands of years old. This is Fort Hill.

"Fort Hill is one of the best-preserved examples of an ancient hilltop enclosure. Fort Hill was built by American Indians of the Hopewell Culture, who lived in Ohio about 2,000 years ago. Despite the name, Fort Hill was not an actual fort used for warfare, but more likely a ceremonial gathering place. Fort Hill is also a nature preserve, and the 1,300 acres are home to one of southern Ohio’s largest mature forests, with many towering old trees." source: www.ohiohistory.org/visit/browse-historical-sites/fort-hill-earthworks-nature-preserve/

"The Hopewell culture flourished in Ohio and other parts of eastern North America during the Middle Woodland Period, possibly as early as 100 B.C. We do not know what these people might have called themselves. The name we use comes from Mordecai Hopewell, a Chillicothe landowner on whose property mounds were excavated in the 1800s.
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The Hopewell culture participated in long-distance trading networks, acquiring copper from the upper Great Lakes, mica from the Carolinas, shells from the Gulf of Mexico, and obsidian from the Rocky Mountains. Magnificent works of art were crafted from these exotic raw materials, such as an elegant human hand effigy cut from mica and giant spear points chipped from obsidian. Hopewell artwork depicts various animals, with deer, bear, and birds appearing most frequently. Animal effigies--perhaps a guardian spirit of a shaman--were carved on the bowls of stone pipes so as to face the smoker." archive.archaeology.org/online/features/hopewell/who_were_hopewell.html

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source: www.carbonmark.com/blog/carbonmark-launches-the-universal-carbon-marketplace

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