Great Serpent Mound (Ohio)
The Great Serpent Mound in southern Ohio is a 1,300-foot effigy earthwork shaped like a coiled serpent, aligned to solstices and lunar cycles. Built around 1070 CE, it stands as the world’s largest effigy mound and a living testament to Indigenous North America’s astronomical and spiritual knowledge.
9/10/20251 min read
📜 Great Serpent Mound (Ohio)
Winding across a high ridge above Brush Creek in southern Ohio, the Great Serpent Mound is the largest effigy earthwork in the world. Measuring more than 1,300 feet in length, it depicts a serpent in graceful curves, ending with a triple-coiled tail at one end and an oval shape at the head that some interpret as an egg, sun, or cosmic portal. Unlike burial mounds, the Serpent is purely symbolic—its form itself is the sacred message.
Scholars have long debated its age and cultural origins. In the 19th century, archaeologists attributed it to the Adena culture (c. 1000 BCE–200 CE) based on nearby burial mounds. More recent radiocarbon dating, however, points to the later Fort Ancient culture (c. 1070 CE). What is undisputed is that its design reflects deep astronomical knowledge: alignments correspond to solstice sunsets and lunar standstills, indicating its use as both a ceremonial site and a sky-watching calendar.
The Serpent Mound was first documented in 1847 by surveyors Ephraim Squier and Edwin Davis, whose drawings brought global attention to Ohio’s earthworks. It was preserved in 1887 when philanthropist Frederic Ward Putnam and the Peabody Museum of Archaeology purchased the land to protect it. Today it is managed by the Ohio History Connection and remains a National Historic Landmark.
The Great Serpent Mound testifies to the brilliance of Indigenous North America: a culture capable of encoding cosmology into the very soil. It is both a mirror of the heavens and a monument of the earth—an enduring reminder that sacred science thrived here long before colonization.
References:
Squier, E.G. & Davis, E.H. Ancient Monuments of the Mississippi Valley (1848)
Lepper, Bradley T. Ohio Archaeology: An Illustrated Chronicle of Ohio’s Ancient American Indian Cultures (2005)
Ohio History Connection: Great Serpent Mound
UNESCO Tentative List: Serpent Mound