The Old Stone Fort State Park in Coffee County preserves a prehistoric enclosure consisting of embankments or “walls” constructed of undressed stacked or piled stone covered with earth. They circumscribe a fifty-acre plateau at the forks of the Duck River. These embankments, originally ranging from four to six feet in height, would have a total length of 4,600 feet if continuous; however, they were only constructed where the stream bluffs are not steep. The enclosure also includes a complex entranceway consisting of a ditch, pedestal mounds on either side of the entrance, and interior parallel walls that run perpendicular to the entrance to form a cul-de-sac. The entranceway configuration convinced many early historians and antiquarians that this was a fortification built by early explorers, possibly Welsh or Norse, or the Spanish troops led by Hernando de Soto. These romantic myths were shattered in 1966, however, when archaeologists from the University of Tennessee proved that this enclosure was built 2,000 years ago by prehistoric Native American groups.
Charcoal recovered from the ditch and embankment provided radiocarbon dates for a sequence of construction phases that span an almost five-hundred-year period, from 80 A.D., when the entrance ditch was dug to 550 A.D., when the cul-de-sac walls were completed. These radiocarbon dates closely correlate with the construction dates of similar hilltop enclosure sites such as Fort Ancient in Warren County, Ohio. The Ohio enclosures are now known to have been constructed by the Hopewell people, a mound-building group of Native Americans who were in contact with cultures in the Southeast during the Middle Woodland period of North American prehistory about two thousand years ago.
Two of these groups that had contact with the Ohio Hopewell people were the McFarland and Owl Hollow cultures of the upper Duck River Valley. Small village sites of these early farming and pottery-making people were excavated by University of Tennessee archaeologists in the nearby Normandy Reservoir before inundation in 1976. As extensive radiocarbon dating from these villages attests, the McFarland people inhabited the upper Duck Valley between 200 B.C. and 200 A.D., with the Owl Hollow people succeeding them between 200 A.D. and 600 A.D. The McFarland culture apparently began constructing the Old Stone Fort in the first century A.D., the enclosure being completed almost five hundred years later by the Owl Hollow culture.
There is now little doubt among anthropologists and archaeologists that the Old Stone Fort was sacred space; however, the actual ceremonial function of this enclosure is still unclear. While a small burial mound may exist outside the walls, there is no direct evidence that the enclosure was used in funerary ritual as were some of the related Hopewell sites in Ohio. The most recent hypothesis is that the Old Stone Fort was some kind of celestial observatory, since the parallel entrance walls seem to point toward the position of the sun at summer solstice.
The Old Stone Fort is now a state archaeological park with an interpretive museum, picnic areas, campgrounds, and playgrounds.