Inventory of Sites Rebuilt or Otherwise Included in EarthWorks

The greatest concentrations of earthworks sites were in the southern part of Ohio. Starting in Newark, the mounds stretch to the southeast along the major tributaries of the Ohio River.

Many of these earthworks were connected. For instance, around Newark, Ohio, some 17  centuries ago, Observatory Circle, the Great Circle and a rectangle that once stood there comprised what was probably the largest geometric earthwork complex ever built anywhere. Constructed from seven million cubic feet of earth, this complex included wide roadways and vast enclosures spread over four square miles in order to mark the movements of the moon as a way of keeping time, as a way of knowing when to plant or harvest crops or when to gather for important festivals.   

Significant examples are also found in Kentucky, Indiana, Illinois and West Virginia.

ADENA CULTURE (600 BC)

Ohio

• Bourneville Earthworks – ditch-and-bank circle in Ross County (lost)
• Miamisburg Mound – second-largest Adena burial mound in the nation (still extant)
• Plains Group Earthworks – a dense group of circles and mounds near Athens, Ohio (Most of this earthworks group is lost.)

Kentucky

• Mount Horeb Ring – a still-extant ring close to a large enclosure near Lexington

West Virginia

• Grave Creek Mound – largest extant Adena burial mound, located near Moundsville, W.V.
• South Charleston Mounds – extensive, complex string of mounds/rings (lost)

HOPEWELL CULTURE (100 BC TO 400 AD)

Adams County, Ohio

• Fort Hill – small hilltop enclosure located along Brush Creek in the Little Miami River Valley, Ohio. It remains untouched from the pioneer era. (still extant)
• Marietta Earthworks – mounds stand among the town’s streets and institutions (Most are still extant.)

Scioto River Valley in Ohio

• Dunlap Earthwork – an unusual rhomboid figure (lost)
• The Great Hopewell Road – might have been North America’s first highway.  Infrared aerial photographs trace fragments of a possible 60-mile, arrow-straight swath from Newark to Chillicothe. (lost)

• High Bank Works – the second of only two circle-and-octagon combinations built. It had the same diameter as Observatory Circle at Newark, 1,050 feet, and both circles and their octagons were aligned to points on the eastern and western horizons defined by the 18.6-year-long lunar cycle. In total, both the High Bank and the Observatory Circle (in Newark) works incorporated the eight major lunar rising and setting points. (Faint remains are extant.)
• Liberty-Harness Earthwork – contained the largest and most architecturally precise of all known Hopewell ceremonial great houses beneath its Great Mound (lost)
• Mound City – the still-visible, restored center of a ten-mile strip of geometric forms in the Scioto River Valley. Mound City covers 13 acres and consists of 23 large burial mounds enclosed by a large, square, earthen wall. (still extant)
• Piketon Earthworks – a circle-and-square design (lost)
• Portsmouth Earthworks – a complex of roadways, rings, mounds and geometric figures (lost)
• Works East Earthwork – three-part geometric site within the city of Chillicothe, Ohio (lost)

Great Miami River Valley, Ohio

• Alexandersville Earthworks – absorbed by the City of Dayton (lost)
• Butler County Hilltop – little known enclosure (still extant)
• Colerain Township Group – geometric and hilltop enclosures (lost)
• Fort Miami Earthworks – located in Shawnee Lookout Park (still extant)

Little Miami River Valley, Warren County and Greene County, Ohio

• East Fork “Gridiron” – a strange labyrinth (lost)
• Fort Ancient – largest prehistoric hilltop enclosure in the country. Because of summertime plant growth and because of its sheer physical size, it’s impossible to view its entire expanse from the ground. Located in the Little Miami River Valley, some of the walls rise as high as two-story buildings. (still extant)
• Fosters Earthworks – held underground fire pits for metal- and rock working (lost)
• Milford Earthworks – absorbed by Milford (lost)
• Pollock Earthworks – today containing only high earthen gateways. These once supported an impressive ten-foot-high wood stockade. The stockade was ceremonially burned, broken and then buried within the earthwork. (lost)

Newark, Ohio, Licking County

• Great Circle Earthwork – 1,200 feet across with 15-foot-high walls (still extant)
• Observatory Circle – nearly perfect circle 1,050 feet across connected to a 610-foot-long octagon and to Observatory Mound, a high, flat-topped mound built against the outer rim of the circle.  (These connected works are still extant; however, a golf course/country club sits upon these ancient monuments.) Observatory Circle also once connected to a 930-foot-long square and to a 1,800-foot-long ellipse containing 12 burial mounds. The square and ellipse have been lost to development.
• Rectangular Enclosure – 740 by 760 feet (only a tiny corner is preserved)

Paint Creek Valley in Ross County, Ohio

• Bear Claw Earthwork – stone bear claw effigy the size of a city block (still extant)

Indiana

• Anderson Earthworks – located along the White River (still extant for the most part)
• New Castle Earthworks – once located along the Blue River (lost)

FORT ANCIENT CULTURE (900 TO 1200 AD)

Adams County, Ohio

• Serpent Mound – 1,360-foot-long snake effigy dating from about 1070 A.D. Located along Brush Creek in south central Ohio. Effigies may have been meant to be seen by the stars or the sun, a means for linking earth with the heavens. Modern archaeologists report that center lines of its coils point to extreme northern rising points of the sun and moon. Its head points to the sunset on the longest day of the year, the summer solstice. (still extant)

Newark, Ohio

• Alligator Mound – effigy in the form of an alligator or possum (preserved near Granville, Ohio)

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