🇺🇸 United States · Earthwork
Old Stone Fort
Middle Woodland 80–550 CE · Middle Woodland (Hopewell-related)
2.75 km stone-walled hilltop enclosure, solstice-aligned, 80–550 CE.
🇺🇸 United States · Earthwork
Toltec Mounds Archeological State Park
Late Woodland – early Mississippian, Plum Bayou 650–1050 CE · Plum Bayou (aboriginal ancestors of Quapaw? Coles Creek related, not Caddo Mississippian)
Best-preserved Plum Bayou-culture platform-mound center (650–1050 CE) – 18 mounds (two tallest 15 m and 12 m) arranged geometrically around rectangular plazas and an earthwork embankment with…
🇺🇸 United States · Ancient village
Pueblo Bonito (Chaco Canyon)
Pueblo II–III · Ancestral Puebloan / Chacoan
Greatest great house of Chaco: D-shaped 800-room complex with 32 kivas, planned in stages 850–1150 CE, aligned to cardinal directions and Chacoan road system radiating 60 km.
🇺🇸 United States · Earthwork
Cahokia Woodhenge
Mississippian Emergent–Early 900–1150 CE · Mississippian (Cahokia)
Mississippian timber Stonehenge: 410 m 48-post solar calendar aligned to Monks Mound solstice.
🇺🇸 United States · Archaeological wonder
Fajada Butte
Pueblo II–III Bonito 1000–1150 CE · Ancestral Pueblo (Chacoan)
Chacoan Sun Dagger butte: three slabs create dagger beam on spirals marking solstices and lunar standstill.
🇺🇸 United States · Earthwork
Watson Brake
Middle–Late Archaic (3500–2800 BCE) · Middle Archaic Watson Brake culture
Oldest North American mound complex: 11 mounds 5400 BP enclosing oval plaza, hunter-gatherer monument without agriculture.