Portsmouth Earthworks

Overview of the Horseshoe Mound

The northernmost section was made up of a number of circular enclosures, two large horseshoe-shaped enclosures, and three sets of parallel-walled roads leading away in different directions. One set of walled roads extends across the Ohio River into South Portsmouth, Kentucky to the southwest to Portsmouth Earthworks, Group A. Another set of walled roads lead to the southeast where it also crossed the Ohio River and lead to Portsmouth Earthworks, Group C.[3] The third set of walled roads lead to the northwest for an undetermined distance, and may point to Tremper Mound and Works, some 5 miles away. The City of Portsmouth maintains a public park which includes one of the remaining horseshoe-shaped enclosures, known as Mound Park, it is the only publicly accessible part of the complex.[2] Under the name Horseshoe Mound it was listed on the National Register of Historic Places in 1974.[2]

In 2019 two independent scholars proposed that the Group B mounds represent part of an eight-mile-long female effigy mound, which the authors propose depicts "The Woman Who Fell from the Sky," a Native American myth about human origins found among the indigenous peoples of North America.[4] If true, this would make it the longest effigy mound known, although much of the structure was destroyed by the city of Portsmouth.[5] The authors link the mounds to the story of He-nau-ee, as told by the Meskwaki Indians, possible descendants of the Hopewell mound builders. Other archeologists have cast doubt on the theory.[6]

One of the surviving walls

Also known as the Old Fort Earthworks (15Gp1) it is a series of rectangular enclosures near South Portsmouth in Greenup County, Kentucky. Group A is a large square enclosure with two series of parallel walls extending from the northeast and southwest corners. The Old Fort Earthworks consist of several sites, including the Old Fort Earthworks (15Gp1), Mays Mound (15Gp16), Hicks Mound (15Gp265), Stephenson Mound (15Lw139), and several other unnamed mounds and enclosures. It is also the location of Lower Shawneetown, a protohistoric/historic Fort Ancient and Shawnee settlement and colonial trading post which are all part of the Lower Shawneetown Archeological District,[7] along with the Thompson and Hansen sites

Group C was a large series of concentric circles surrounding a high central conical mound. This section of the earthworks is located in Greenup County, Kentucky several miles to the east of South Shore, but connected to Group B by a causeway that ran down to the Ohio River.

Artists conception of the Biggs site

Located to the west or downriver of Group C is the Biggs site (15Gp8) or Portsmouth Earthworks Group D. Biggs was an Adena culture circular causewayed embankment 5 feet (1.5 m) high by 30 feet (9.1 m) wide encircling a ditch 6 feet (1.8 m) deep and 25 feet (7.6 m) across. They encompassed an area 90 feet (27 m) in diameter. In the center of the ditch was a conical tumulus 8 feet (2.4 m) high and 40 feet (12 m) in diameter. It was not only mapped by Squier and Davis, they also included a small illustration of the feature.[8]