Serpent Mound

The Great Serpent Mound is a 1,348-feet-long (411m), three-feet-high prehistoric effigy mound located in Peebles, Ohio. It was built on what is known as the Serpent Mound crater plateau, running along the Ohio Brush Creek in Adams County, Ohio. The mound is the largest serpent effigy known in the world.

The first published surveys of the mound were by Ephraim G. Squier and Edwin Hamilton Davis, featured in their historic volume, Ancient Monuments of the Mississippi Valley (1848), that was commissioned by the Smithsonian Institution.

The United States Department of Interior designated the mound as a National Historic Landmark in 1966. The mound is maintained through the Ohio History Connection, a nonprofit organization dedicated to preserving historical sites throughout Ohio.

Effigy mounds have been constructed independently by several cultures. The significance of Serpent Mound is based on its size and historical relevance. Made up of three parts, Serpent Mound extends over 1,376 ft (419 m) in length, varying from 9 in (23 cm) to more than 3' (30–100 cm (12–39 in)) in height. The mound stands with a width varying between 20 and 25 ft (6.1 and 7.6 m) based on the section. Serpent Mound conforms to the surrounding land, as it was built on a bluff above the Ohio Brush Creek. The mound winds back and forth for more than eight hundred feet, with its tail coiling in seven areas throughout the mound. The mound features a triple-coiled tail at the end of the structure, often viewed as a benchmark of the mound. Yellowish clay and ash make up the main constituents of the mound, with a layer of rocks and soil reinforcing the outer layer.

The generally accepted interpretation of the structure is that of an open-mouth head of a serpent nearly engulfs a hollow oval feature that faces the east and is 120-foot (120 ft)-long. This oval feature may represent an egg, with an apparent depiction of the snake consuming it, however, many anthropologists believe that the oval is a representation of the Sun, or the body of a frog. Other scholars think it is the remnant of a platform mound. The western side of the effigy features a triangular mound approximately 31.6 ft (9.6 m) at its base and long axis, reminiscent of other existing serpent effigies in Canada and Scotland.

Throughout the twentieth century, anthropologists and archaeologists had disputed which culture and people had created the Serpent Mound, as may be seen in a overview published by the Metropolitan Museum of Art in 2002. The Ancient Earthworks Project published "New Radiocarbon Dates Suggest Serpent Mound is More Than 2,000 Years Old" (July 2014). The article provided evidence supporting attribution of the mound to the Adena peoples around 300 BCE (2300 years ago) and refers to radiocarbon data that was published later in an October 2014 article in The Journal of Archaeological Science. These scholars also conclude that the mound was renovated around 1400 CE by Fort Ancient peoples.

In 2019, Monaghan and Hermann published additional research in an article in The Midcontinental Journal of Archaeology that supports their earlier conclusions. They corroborated the 2014 research and refined the radiocarbon dates. Monaghan and Hermann determined that the mound was built around 2,100–2,300 years ago (300-100 BCE) during the Adena period and that it was subsequently rebuilt (or repaired) about 900 years ago (1100 CE) during the Fort Ancient period. They provided a reconciliation of the radiocarbon dating differences among samples.

In 2018, archaeologist Brad Lepper published a response questioning the attribution of construction to the Adena culture. Lepper et al. pointed out that the dates obtained by Herrmann and Romain are of poor quality. The material the team dated is not charcoal, but “organic sediment” (Herrman et al. 2014:119). Moreover, the samples were obtained from soil cores and not an exposed stratigraphic profile, so the resulting dates are known to be problematic. Henriksen et al. (2019) have demonstrated that such dates can be as much as 3,000 years older than the actual age of a mound. Moreover, the Adena culture is not known to have built effigy mounds or to have used serpent symbolism in their art, whereas the Fort Ancient culture built the Ohio Alligator Mound and frequently depicted serpents in their art. These assessments conclude that the best available data indicate that Serpent Mound was built by the Fort Ancient culture.