The Hopewell Culture

At a glance

Origins: a shopkeeper's name and a world's fair

The Hopewell culture is named after a Chillicothe dry-goods merchant, Mordecai Cloud Hopewell, who ran Clough & Hopewell Dry Goods downtown and in 1889 bought the two farms on the North Fork of Paint Creek that held a cluster of mounds and earthworks then known as "Clark's Work," a name Ephraim Squier and Edwin Davis had used in their 1848 survey (UNESCO nomination, 2.b; Moorehead 1922, preface).

The dig that made the name famous was driven by the 1893 World's Columbian Exposition in Chicago. Harvard's Frederic Ward Putnam, running the exposition's Department of Anthropology, appointed young Warren King Moorehead his Ohio field assistant around January 1891. After working at Fort Ancient and Oregonia, Moorehead moved his crew to "Mr. M. C. Hopewell's farm" at the end of August 1891 and, over the following two seasons, excavated at least 17 mounds, including roughly a quarter of the giant Mound 25 (Moorehead 1922; UNESCO nomination, 2.b). "In honor of the owner, M. C. Hopewell, we changed the name from Clark's Works to Hopewell Group," Moorehead wrote (Moorehead 1922, p. 83). The finds went on display at the exposition and then to Chicago's new Field Museum of Natural History, where they remain; following archaeology's convention of naming a culture for the site where its defining evidence turned up, "the concept of Hopewell was born" (UNESCO nomination; NPS, Hopewell Mound Group). The nomination itself records an objection from Marti Chaatsmith, a Comanche Nation citizen, that carrying "the name of a Chillicothe merchant" amounts to "a colonial imposition on a sacred, Indigenous place" (UNESCO nomination).

Whatever it is called, Hopewell was never a tribe or a single people. The UNESCO nomination describes it as "a religious movement that linked many distinct communities, likely with differing languages," scattered across much of eastern North America with its heartland in southern Ohio (UNESCO nomination, 2.b). Archaeologists Seeman and Nolan describe it as "perhaps best interpreted" as an early American Indian socioreligious movement with distinct shrine or cultic centers (Seeman & Nolan 2023). People lived in small hamlets of a few households scattered along floodplains and terraces, grouped into local communities six to 11 kilometers across; there were no towns, no palaces and no large dwelling houses (UNESCO nomination). Skeletal evidence shows that even people buried with rich regalia "ate the same foods and worked just as hard as everyone else," and there is no systematic evidence of children buried as inherited leaders (UNESCO nomination; OHC blog).

A 2023 re-analysis of 425 screened radiocarbon dates from Ohio Hopewell sites puts the culture's start at about AD 90-120 and its main activity ending around AD 395-430 -- a tighter, later window than the popular "100 BC to AD 500" figure still seen in many summaries (Seeman & Nolan 2023). Ancient DNA from 34 people buried at the Hopewell Mound Group links them to earlier Adena and Glacial Kame burials, supporting the idea that Hopewell grew out of Ohio's own earlier mound-building traditions rather than arriving from elsewhere (OHC blog).

Geometry, the moon and a "Hopewell unit"

In 1980, Earlham College's Ray Hively (physics) and Robert Horn (philosophy) resurveyed the Newark Octagon with a transit and steel tape. Their 1982 paper showed the whole figure could be laid out from one measurement: the 321.3-meter diameter of the Observatory Circle, a length they called the OCD (Hively & Horn 1982). That figure -- 321.3 meters, or 1,054 feet, popularly called the "Hopewell unit" -- recurs across the region: at High Bank's circle (322 m), in the cross-width of Hopeton's circle, the diagonals of Mound City, the sides of the squares at five Paint Creek/Scioto "tripartite" earthwork complexes, and the lost circles at Circleville and Seal Township (Ohio Capital Journal 2025; UNESCO nomination, 2.a and 3.1). The Observatory Circle's own construction is remarkably precise: its measured circumference of 1,008.6 meters comes within about a meter of a perfect circle's 1,009.4 meters (Hively & Horn 1982; UNESCO nomination).

Hively and Horn's most striking finding was astronomical, not just geometric. The Octagon's main axis -- running from the Observatory Mound, through a parallel-walled avenue and across the Octagon itself -- points to the northernmost moonrise of the moon's 18.6-year cycle, a rare event the nomination says the far gateway captures "within 0.2 degree" (Hively & Horn 1982; UNESCO nomination, 2.a). Historian Brad Lepper recounts that the two men came to Newark expecting to demonstrate how easy it is to find chance alignments in a monument this large; they found no solar alignments at the Octagon, and only then found the lunar ones (WOSU 2025). In 1984 the pair reported the same lunar geometry at High Bank Works near Chillicothe, the only other earthwork combining a circle and an octagon; High Bank's circle matches Newark's almost exactly, and the two sites' main axes, 103 kilometers apart, sit at right angles to each other, according to the nomination (Hively & Horn 1984; UNESCO nomination, 2.a).

UNESCO's evaluators accepted the underlying geometry but stopped short of endorsing every astronomical claim built on it. The international review body ICOMOS judged that "some claims related to the astronomical alignment aspect would need further deliberation," and the World Heritage Committee's own recommendation calls for "facilitating more research and deliberation on the astronomical alignments" (ICOMOS; Decision 45 COM 8B.47). Lepper's own reading leans less toward "observatory" and more toward a sacred mechanism: the earthworks, he has written, were built "to serve as a giant gear that meshed with the clockwork mechanisms of the heavens" (OHC blog).

The great earthworks

Newark's complex, spread across the modern towns of Newark and Heath in Licking County, once covered roughly 4.5 square miles (Ohio Supreme Court, 2022-Ohio-4345). Today its surviving pieces are the Octagon, about 16.5 hectares (roughly 41 acres, not the "50 acres" still commonly quoted from an 1848 survey), joined to the 321-meter Observatory Circle; the Great Circle, about 358 meters across with an inner ditch eight to 12.5 meters wide; and the small Wright Earthworks fragment (UNESCO nomination, 2.a; OHC, A View Within the Circle). No artifacts have ever been found inside the Octagon itself (UNESCO nomination). At the center of the Great Circle, archaeologist Emerson Greenman dug Eagle Mound in 1928 and found no burials, only the postholes of a large rectangular building beneath it (OHC, A View Within the Circle). From 1896 to 1924 the Great Circle doubled as Idlewilde Park, a small amusement park complete with a switchback railroad and a Ferris wheel (OHC blog).

Near Chillicothe in Ross County sit six more of the eight World Heritage components. Mound City Group holds 25 mounds inside a rounded square wall, the densest concentration of burial mounds at any Hopewell site; Squier and Davis dug there in 1846 and, in one mound alone, found "not far from two hundred pipes, carved in stone" (Squier & Davis 1848; NPS, Mound City Group). Across the Scioto River, Hopeton Earthworks pairs a rounded square with a circle of nearly equal area and has produced more radiocarbon dates than any other Ohio Hopewell site (UNESCO nomination). High Bank Works, south of Chillicothe, carries the second Newark-sized circle-and-octagon pair and today survives only as a plowed field, visible clearly in LiDAR (NPS, High Bank Works). The Hopewell Mound Group itself, on the North Fork of Paint Creek, is the largest Hopewell enclosure at 55.34 hectares; its Mound 25 held at least 102 burials and two "Great Deposits," one holding all the site's black obsidian and the other all its white pearls (UNESCO nomination, 2.a and 2.b). Under a second mound there lay more than 8,000 flint discs -- 8,185 by Moorehead's own count -- carried from sources in Tennessee, Illinois and Indiana up to 700 kilometers away (Moorehead 1922; UNESCO nomination). Seip Earthworks, further southwest near Bainbridge, encloses about 36 hectares and yielded thousands of freshwater pearls, silver, galena, meteoric iron, alligator and shark teeth, and woven milkweed cloth (UNESCO nomination).

The eighth component, Fort Ancient in Warren County near Oregonia, is the largest Hopewell hilltop enclosure: 5.6 kilometers of walls around 40.41 hectares on a bluff 82 meters above the Little Miami River. The name is a trap -- early settlers assumed the massive walls were a military fortification, and a much later, unrelated farming people that lived nearby from roughly AD 1000 to 1650 was named the "Fort Ancient culture" only because one of its villages was found inside the older walls (UNESCO nomination, 2.a and 2.b). Ohio bought the first 180 acres of the site in 1891, making it the state's first state memorial (UNESCO nomination, 5; Fort Ancient NHL nomination).

Not every geometric earthwork survived to be inscribed. At Circleville in Pickaway County, Squier and Davis in 1848 described a circle and square, "now almost entirely destroyed," that had shared the Newark Observatory Circle's exact 321-meter diameter; the town platted inside the circle in 1810 was rebuilt into a square street grid by 1856, erasing what remained (Squier & Davis 1848; UNESCO nomination; Wikipedia, Circleville). At the Muskingum-Ohio confluence in Marietta, Washington County, a 50-acre enclosure survives only in fragments; its conical Conus mound, now inside Mound Cemetery, is the one intact piece (Wikipedia, Marietta Earthworks). Near Portsmouth in Scioto County, the Portsmouth Works once spread across both banks of the Ohio River; today only the Horseshoe Mound survives, inside the city's Mound Park (Wikipedia, Portsmouth Earthworks).

A continent-wide network

Almost nothing valuable at these sites was local. Obsidian, which forms only near volcanoes, came from the Yellowstone region more than 1,500 miles away; a 1966-1968 chemical study of 87 obsidian artifacts from 30 Hopewell sites across six states and Ontario matched 68 pieces to Yellowstone's Obsidian Cliff, including 36 of 47 pieces tested from four Ohio sites alone (NPS, Hopewell Culture Obsidian; Gordus, Griffin & Wright 1968). Because obsidian is nearly absent along the route between Wyoming and Ohio, the National Park Service concludes it was likely carried directly by people traveling to the ceremonies rather than passed village to village (NPS obsidian). Copper came mostly from around Lake Superior, nearly 800 miles away; sheet mica came from the Blue Ridge of western North Carolina, more than 400 miles from Mound City; marine shell, likely from Florida's Gulf coast, and fossil shark teeth traveled 500 miles or more; and flint from a nearly eight-mile vein at Flint Ridge, in Licking and Muskingum counties, traveled the opposite direction -- about a quarter of the bladelets tested from Pinson Mounds in Tennessee were made of Flint Ridge flint (NPS, Hopewell Culture Copper; NPS, Mica; NPS, Seashells; OHC, Flint Ridge; OHC blog). The nomination reads this one-way flow of exotic raw material into Ohio, without matching goods moving back out, as evidence of pilgrimage and gift-giving rather than ordinary trade (UNESCO nomination, 3).

The masterpieces made from these materials still circulate the world. Mound City's cache of effigy pipes, unearthed by Squier and Davis in 1846, was sold by collector Edwin Davis to an English buyer in 1864 for $10,000 and passed to the British Museum in 1931, where one pipe was later chosen among the 100 objects for the museum's "History of the World in 100 Objects" (OHC blog; OHC blog). The copper birds excavators pulled from Mound City's Mound 7 in 1920 were called eagles at the time; the National Park Service now calls them falcons and uses them as the park's symbol (Mills 1922; NPS copper). A single copper axe from Mound 25 weighs about 17 kilograms, some 37 pounds -- Moorehead called it the largest finished copper object made by any prehistoric people in the region (UNESCO nomination).

The Octagon and the golf course

For 114 years, from 1910 to 2024, the Octagon Earthworks operated as a private country club's golf course. The club leased the site from the Newark Board of Trade and, later, from the state historical society that took ownership in 1933; a brick clubhouse built in 1964 displaced about 30 meters of the Observatory Circle wall inward by roughly four meters (OHC, Objects from the Octagon; UNESCO nomination). In its final years the public's access was limited to a viewing platform and, by one account, four open days a year, and Ohio History Connection told the courts that since 2003 the club had made access "nearly impossible" (OHC 2019; Court News Ohio 2022). After years of negotiation, an appraisal dispute and a lawsuit filed in November 2018, the Supreme Court of Ohio ruled 6-1 on December 7, 2022, that the state could take back the lease, writing that the Octagon's significance "is arguably equivalent to Stonehenge or Machu Picchu" (Ohio Supreme Court, 2022-Ohio-4345). UNESCO inscribed the site in September 2023 while the value of the taking was still headed for a jury trial; Ohio History Connection and the club settled for a confidential sum in August 2024, and the club used the money to buy and convert Newark's public Trout Club golf course into a private one (Decision 45 COM 8B.47; WVXU 2024). Full public access began on January 1, 2025, drawing about 800 visitors on the first day, and Ohio History Connection has since let the grass on the walls grow long and begun a multi-year removal of sand traps and tee boxes (Statehouse News Bureau 2025). In 2026, USA Today's 10Best readers voted the Octagon the country's best new attraction (Hopewell Ceremonial Earthworks).

Descendant nations and UNESCO

The World Heritage Committee inscribed the Hopewell Ceremonial Earthworks on September 19, 2023, by consensus, as the United States' 25th World Heritage Site, qualifying under criteria for a masterpiece of human creative genius and for exceptional testimony to a cultural tradition (Decision 45 COM 8B.47; OHC). The property, split across Licking, Ross and Warren counties, totals 320.7 hectares with 561.8 hectares of buffer zones (ICOMOS).

The nomination is direct about ancestry: the earthworks "lack any known affiliation with a specific modern tribe," though their themes echo Eastern Woodland traditions of the Shawnee, Delaware (Lenape), Miami (Myaamia), Ottawa, Wyandotte, Seneca-Cayuga, Osage and other nations (UNESCO nomination, 3). No federally recognized tribe is headquartered in Ohio today; the state's Native nations were forced out by the 1840s (WVXU 2024; UNESCO nomination, 2.b). Ohio History Connection consults 45 tribal nations with historic ties to Ohio each year at its Tribal Nations Conference, and its chief historic sites officer, Jennifer Aultman, has said the earthworks are simply too old to trace to any one tribe (Statehouse News Bureau 2025). Eastern Shawnee Chief Glenna Wallace has written, in the nomination itself, that her people "treasured these mounds. Perhaps they did not build them, but they loved them, protected them, revered them" -- offered as her nation's own heritage and oral tradition, not a genetic finding (UNESCO nomination, 3). Genetic studies of Hopewell Mound Group burials have so far pointed in more than one direction, with tentative ties suggested to several different modern reference populations, underscoring that no single line of descent has been established (OHC blog).

By around AD 400, forests were reclaiming the great enclosures and no new ones were being built; the nomination is careful to say the builders "did not move away or die off, but stopped building mounds," with cultural continuity running to about AD 650 (ICOMOS; UNESCO nomination, 2.b). A widely reported 2022 study proposing a comet airburst as the cause of Hopewell's decline was retracted by its journal in 2023 after a rebuttal from twelve researchers found it misread its own sources and dates (Nolan et al. 2023; Retraction note). What actually ended the great building projects remains an open question.

Sources

• UNESCO World Heritage nomination dossier, Hopewell Ceremonial Earthworks
• ICOMOS evaluation report 1689 (2023)
• World Heritage Committee Decision 45 COM 8B.47
• Seeman & Nolan 2023, "Building the Ohio Hopewell Chronology," American Antiquity
• Hively & Horn 1982, "Geometry and Astronomy in Prehistoric Ohio"
• Hively & Horn 1984, "Hopewellian Geometry and Astronomy at High Bank"
• Moorehead 1922, "The Hopewell Mound Group of Ohio"
• Squier & Davis 1848, "Ancient Monuments of the Mississippi Valley"
• Gordus, Griffin & Wright 1968, obsidian sourcing study
• Ohio Supreme Court, 2022-Ohio-4345
• Ohio History Connection, Hopewell Ceremonial Earthworks inscription release
• Ohio History Connection, A View Within the Circle
• Ohio History Connection, Objects from the Octagon
• NPS, Hopewell Culture National Historical Park articles
• Statehouse News Bureau 2025, two years after designation
• WVXU 2024, Octagon Earthworks open to the public
• Ohio Capital Journal 2025, on the earthworks and their controversies