🇺🇸 United States · Earthwork
Newark Earthworks
Hopewell culture 100 BCE–500 CE · Hopewell (Adena descended, Algonquian? cohort)
Hopewell giant geometric enclosures marking 18.6-yr lunar cycle.
🇺🇸 United States · Earthwork
Alligator Mound
Late Woodland / Fort Ancient 800–1200 CE · Fort Ancient (Late Woodland)
Effigy mound 205 ft/62 m long, 4–6 ft high, head oriented SW tail NE, depicting an opossum/underwater panther effigy on bluff south of Granville. Listed NRHP 1971.
🇺🇸 United States · Earthwork
Great Serpent Mound
Disputed: either Adena 320 BCE–200 CE or Fort Ancient 1070–1200 CE (latest C14 favors Fort Ancient 1120 CE) · Adena culture or Fort Ancient culture
Quarter-mile (411 m) effigy mound in shape of serpent with oval head swallowing an egg, 3 ft high, coiled tail atop meteor-crater plateau above Ohio Brush Creek, largest surviving effigy mound in…
🇺🇸 United States · Earthwork
High Bank Works
Hopewell Middle Woodland 100–400 CE · Hopewell tradition
Circle-octagon pair 320 m circle, UNESCO 2023.