Great Serpent Mound
The Great Serpent Mound.jpg
The Great Serpent Mound
ancient Native American effigy
Serpent Mound is located in Ohio
Serpent Mound
Serpent Mound is located in the United States
Serpent Mound
Nearest cityPeebles, Ohio
Coordinates39°01′35″N 83°25′51″W / 39.02639°N 83.43083°W / 39.02639; -83.43083Coordinates: 39°01′35″N 83°25′51″W / 39.02639°N 83.43083°W / 39.02639; -83.43083[2]
NRHP reference No.66000602[1]
Added to NRHPOctober 15, 1966


Ohio historical marker

The Great Serpent Mound is a 1,348-foot-long (411 m), three-foot-high prehistoric effigy mound located in Peebles, Ohio. The mound itself resides on the Serpent Mound crater plateau, running along the Ohio Brush Creek in Adams County, Ohio. The mound is maintained through the Ohio History Connection, a non profit organization dedicated to preserving historical sites throughout Ohio. The United States Department of Interior later designated the mound as a National Historic Landmark. The Serpent Mound was first reported through surveys by Ephraim Squier and Edwin Davis. It was featured in their historic volume Ancient Monuments of the Mississippi Valley, published in 1848 by the newly founded Smithsonian Museum. The mound has received a lot of attention, being the largest serpent effigy in the world to this day.

Effigy mounds can be traced back throughout several civilizations. The significance of The Serpent Mound stems greatly from its size and historical relevance. Made up of three parts, The Serpent Mound extends over 1,376 feet (419 m) in length, varying from 9" to over 3' (30–100 cm) in height. The mound stands with a width varying between 20 and 25 feet based on the section.The Serpent Mound conforms to the surrounding land, as it rests on the bank of the Ohio Brush Creek. The mound itself winds back and forth for more than eight hundred feet, with its tail coiling in seven areas throughout the mound itself. 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 acts as the main constituent of the mound, with layer of rocks and soil reinforcing the outer layer. The open-mouth head of the serpent itself wraps around an east facing, 120-foot (37 m)-long, hollow oval feature. The feature is representative of an egg, with an apparent depiction of the snake consuming it. Many scholars presume that the oval is a representation of the sun, the body of a frog, or merely the remnant of a platform. The western side of the effigy features a triangular mound approximately 31.6 feet (9.6 m) at its base and long axis, reminiscent of other serpent effigies in Ontario and Scotland.

Origin and chronology

In previous years, the civilization responsible for the creation of the Serpent Mound had been highly disputed amongst archaeologists, as can be seen in the material published in 2002.[3] Its construction was often attributed to different civilizations. Very little additional evidence, such as artifacts and burials, can be found at the site of the mound, leaving it hard for archaeologists to trace its construction back to one civilization. Archaeologists generally acknowledged that the Adena culture (800 BC to 100 AD) and the Fort Ancient Culture (1000 to 1750 AD) as the main contributors to the mound's creation. They argued that the Adena culture completed a majority of their contribution to the mound around 320 BC, while the Fort Ancient Culture contributed some work around 1070 AD.

The mound's lack of physical artifacts has led archaeologists to rely on radiocarbon dating to determine when the mound was created. An article published in July 2014, titled "New Radiocarbon Dates Suggest Serpent Mound is More Than 2,000 Years Old",[4] provides evidence supporting the mound's creation by the Adena culture around 300 BC (2300 years ago). The article references the radiocarbon data that was published in October 2014 by "The Journal of Archaeological Science".[5] Furthermore, these scholars argued that it was renovated around 1400 AD by Fort Ancient Culture.

In 2019, additional research was published in "The Midcontinental Journal of Archaeology" by Monaghan and Hermann.[6] These scholars corroborate the 2014 research, and refine the radiocarbon dates. Monaghan and Hermann determined that the mound was built around 2,100–2,300 years ago (300-100 BC) during the Adena period, but was subsequently rebuilt (or repaired) about 900 years ago (1100 AD) during the Fort Ancient period.

Nevertheless, archaeologist Bradley Lepper recently expressed some doubt about the connection with the Adena culture.[7]

The Serpent Mound at Rice Lake in Peterborough County, Ontario, Canada, dating over 2000 years old, has been linked with the Adena culture.[8]

Prehistory of Ohio

Main article: Prehistory of Ohio

The spiral at the tail of The Serpent Mound
The spiral at the tail of The Serpent Mound

Several groups of Paleo-Indians (13000 B.C. to 7000 B.C.) occupied the land in Ohio prior to the Adena and Hopewell cultures. Evidence shows that numerous civilizations of Paleo-Indians occupied the land in Ohio, thriving through hunter-gatherer techniques, and ranged throughout the land. The Paleo-Indians hunted large game such as mastodon. Archaeologists have found remains of more 150 mastodons in Ohio alone,[9] as well as the remains from other large game. The most complete mastodon skeleton was excavated at the Burning Tree Mastodon site.

Clovis point spear heads have been found that indicate interaction with other groups of Paleo-Indians that also hunted large game.

The Paleo Crossing site and Nobles Pond site tools, like spear-throwers, were more sophisticated. Base camps were established for winter lodging. The Glacial Kame culture, a late Archaic group, traded for sea shell and copper with other groups and were used as a sign of prestige within the group, for respected healers and hunters. The objects were buried with their owners.[10]

Following the ancient Paleo-Indians, the Woodland Period (800 B.C. to A.D. 1200) of the Post-Archaic Period is known for its rich ritual and artistic life and well-developed villages. The Woodland Period is well known for the emergence of earthworks and mounds, which were commonly used for burials as well. Along with hunted and gathered for their food and game, many civilizations cultivated crops such as maize, squash and beans. The Adena and Hopewell cultures flourished during the Early and Middle Woodland periods, while the population of the Woodland people expanded dramatically. Several groups of the Woodland people lived in larger villages, surrounded by defensive walls or ditches that were built for protection. Ritual and artistic endeavors waned during the Late Woodland period, as well as trading amongst other groups. Many of the earthworks and effigy mounds were built early on in this period, while these cultures lack construction of new mounds after their inception.[11]

During the late prehistoric period (900 A.D. to 1650 A.D.) the villages of civilizations such as the Adena people and the Fort Ancient people were much larger. These villages were often built on a higher ground near a river, commonly surrounded by a wooden stockade. After a long hiatus, civilizations returned to building earthworks and effigy mounds, but not as frequently as during the Woodland period.[11]

Civilizations of the Midwest

The Adena culture

The Adena culture consists of the pre-contact American Indian culture that lived throughout the midwest in states such as Kentucky, Indiana, Pennsylvania, West Virginia and most predominantly Ohio. The majority of these civilizations inhabited the Scioto River and Hocking Valleys in southern Ohio, as well as the Kanawha Valley near Charleston, West Virginia. This period is often referred to as The Early Woodland Period, ranging between 800 B.C. and 1 A.D. The name “Adena” refers to the culture that once inhabited this land rather than a singular group or tribe. The name originates from the estate of Ohio Governor Thomas Worthington, which can be found about one and a half miles northwest of Chillicothe, Ohio. The estate itself belongs to a small town in Ohio called Ross County, which Worthington referred to as “Adena”, a Hebrew name that “was given to places for the delightfulness of their situations”. Worthington's estate was previously home to an ancient burial mound, standing 26 feet tall, hence the name "The Adena Mound".

Archaeologists attribute the creation of these civilizations to the Adena culture as a whole, though are unsure of the specific tribes that inhabited the land. The title is used out of archaeological convenience, that encompasses similarities in artifact style, architecture, and other cultural practices, allowing archaeologists to distinguish the Adena culture from other cultures in the region at different time periods. The Adena Mound site became the "type site" of the culture itself due to its exemplification of all the culture's significant features. In light of this, the site's title was later applied to the entire culture.[12]

As were many of the tribes of the Woodland period, the Adena people were hunter-gatherers. As well as hunting large game and reaping the lands crop, the Adena people survived through domesticating various crops such as squash, sunflower, sumpweed, goosefoot, knotweed, maygrass, and tobacco.[13] They often lived in small villages with surrounding gardens but moved frequently to follow various animal herds while planting and feeding on various types of nuts along the way. In addition to undertaking small-scale horticultural production, the Adena people are also known for their production of clay pottery, having been one of the first to cultures to bring it to Ohio. Observed through remains found at the type site, achaeologists characterize the Adena's clay pottery through its large, thick-walled vessels, resembling a modern-day bowl. Archaeologists believe that this clay pottery was used to cook ground seeds into an oatmeal-like substance.

The Adena were known for their burial practices, having buried their dead in prominent mounds throughout the midwest. Many archaeologists believe that these structures served as territorial markers for the Adena people. The mounds themselves were often accompanied by small circular earthen enclosures that many archaeologists believe were once used for rituals. The Miamisburg Mound in Montgomery County, Ohio, is home to the largest Adena burial mound in the state. Mounds such as this hosted multiple burials, characterized by the rituals performed and the funerary objects worn such as bracelets, ear spools, gorgets and other ornaments. Larger ornaments such as bones and stone tools were often worn around the neck. The deceased individual was either cremated or placed on their back in timber-lined tombs.[14]

By around the time of A.D. 1, the Adena culture began to decline and their civilizations began to evolve into what is known as The Hopewell culture. Numerous Adena groups began to build larger earthworks and effigy mounds, expanding their efforts to acquire exotic raw materials such as copper and mica. Many people of The Hopewell culture continued to follow the old ways of the Adena people. In some regions, including Southwestern Ohio, the Adena way of life persisted well into the first century A.D. through the efforts of these people.

The Fort Ancient Culture

Main article: Fort Ancient Culture

Map of Fort Ancient from 1848
Map of Fort Ancient from 1848

The Fort Ancient Culture refers to the Native American Cultures that flourished from 1000 C.E. to 1750 C.E., predominantly inhabiting land near the Ohio River valley. These civilizations flourished in the modern-day regions of southern Ohio, northern Kentucky, southeastern Indiana and western West Virginia. The Fort Ancient tribes are often referred to as a "sister culture" of the Mississippian culture, though can be distinguished through the time period in which they thrived and their many cultural differences. Along with their relation to the Mississippian culture, evidence suggests that the Fort Ancient Culture were not the direct descendants of the Hopewellian Culture. Despite what many believe, the tribes of the Fort Ancient Culture were not responsible for the creation of The Great Serpent Mound, though contributed to its physical appearance through maintenance around 200 A.D.

The name of the culture originates from the Fort Ancient, Ohio archeological site. However, the Fort Ancient Site is now thought to have been built by Ohio Hopewellian people, having later been occupied later by the succeeding Fort Ancient culture. The site is located on a hill above the Little Miami River, close to Lebanon, Ohio. Despite its name, most archaeologists do not believe that Fort Ancient was used primarily as a fortress by either the Ohio Hopewell culture or the Fort Ancient Culture. Archaeologists believe that it was more likely used as a ceremonial location.

Fort Ancient tools found in Maysville, KY
Fort Ancient tools found in Maysville, KY

In 1996, the team of Robert V. Fletcher and Terry L. Cameron (under the supervision of the Ohio Historical Society's Bradley T. Lepper) reopened a trench created by Frederic Ward Putnam of Harvard over 100 years before. They found a few pieces of charcoal in what was believed to be an undisturbed portion of the Serpent Mound. However, bioturbation, including burrowing animals, frost cracks, etc., can reverse the structural timeline of an earthen mound such as Serpent Mound. It can shift carbon left by a later culture on the surface to areas deep within the structure, making the earthwork appear younger.

When the team conducted carbon dating studies on the charcoal pieces, two yielded a date of ca. 1070 AD, with the third piece dating to the Late Archaic period some two thousand years earlier, specifically 2920+/-65 years BP (before the present). The third date, ca. 2900 BP, was recovered from a core sample below cultural modification level. The first two dates place the Serpent Mound within the realm of the Fort Ancient culture. The third dates the mound back to very early Adena culture or before.[15]

The Fort Ancient people contributed to maintaining and refurbishing The Great Serpent Mound though were not responsible for its creation. The rattlesnake is significant as a symbol in the Mississippian culture, helping us to understand the significance of the mound's shape. When attempting to identify the species of snake, there is no sign or indication of a rattle.[15]

Very few, if any, artifacts from The Fort Ancient people can be found at the site of The Great Serpent Mound. As just like the Adena people, the Fort Ancient Culture often buried artifacts in its mounds. Along with a lack of artifacts found, the Fort Ancient people were not known to bury their dead in the same manner as the Adena culture, especially in proximity to the effigy.[15]

Another effigy mound found in Ohio, the Alligator Effigy Mound in Granville, Ohio, was carbon dated to the Fort Ancient period.

Meaning of the mound

The curvature of The Serpent Mound
The curvature of The Serpent Mound

Having been built around 1070 A.D., many archaeologists believe that the mound's creation could have been influenced by two different astronomical events: the light from the supernova that created the Crab Nebula in the year 1054 A.D. and the appearance of Halley's Comet in 1066 A.D. The light of the supernova would have been visible for two weeks after it first reached earth, which could even be seen in broad day light. As a secondary theory, archaeologists assumed that the tail of Halley's Comet could have influenced the shape of the mound. Through through observation, the tail of the comet has always appeared as a long, straight line and does not resemble the curves of the Serpent Mound. Numerous other supernovas may have occurred over the centuries that span the possible construction dates of the effigy, though these two influences remain the most prominent theories.

The mound is located on the site of a classic astrobleme, an ancient meteorite impact structure. When attempting to understand the impact origin of this structure, the pattern of disruption of sedimentary strata has provided archaeologists with a lot of information. In the center of the structure, strata have been uplifted several hundred feet, resembling the central uplifts of lunar craters of the Copernicus. In 2003 geologists from Ohio State University and the University of Glasgow (Scotland) corroborated the meteorite impact origin of the structure at The Serpent Mound. They had previously studied core samples collected at the site in the 1970s, providing them with a background of information pertaining to the site. Further analyses of the rock core samples indicated that the impact occurred during the Permian Period, about 248 to 286 million years ago. This has led archaeologists to believe that the topographic expression of this impact or the impact crater, has been completely erased by erosion.

In 1987, Clark and Marjorie Hardman published their finding that the oval-to-head area of the serpent is aligned to the summer solstice sunset. A depiction of the serpent mound that appeared in The Century periodical in April 1890, drawn by William Jacob Baer.


A depiction of the serpent mound that appeared in The Century periodical in April 1890, drawn by William Jacob Baer.
A depiction of the serpent mound that appeared in The Century periodical in April 1890, drawn by William Jacob Baer.

Ancient Monuments of the Mississippi Valley fascinated many across the country, including Frederic Ward Putnam of the Peabody Museum of Archaeology and Ethnology at Harvard University. Putnam spent much of his career lecturing and publishing on the Ohio mounds, specifically the Serpent Mound. When he visited the Midwest in 1885, he found that plowing and development were destroying many of the mounds, removing significant history of these cultures and their burial sites. In 1886, with help from a group of wealthy women in Boston, such as The Glass Flowers' patroness Mary Lee Ware, Putnam raised funds to purchase 60 acres (240,000 m2) at the site of The Serpent Mound in hopes to ensure its preservation. Along with The Serpent Mound, the purchase also contained three conical mounds as well as a village site and burial place. The Serpent Mound is now listed as a "Great Wonder Of the Ancient World" by National Geographic Magazine.

The mound was originally purchased on behalf of the Trustees of the Peabody Museum, in 1900 the land and its ownership were granted to the Ohio State Archaeological and Historical Society (a predecessor of the present Ohio Historical Society). The Ohio Historical Society has designated the Arc of Appalachia Preserves system, a project of Highlands Sanctuary, Inc., as the managing agency of Serpent Mound from 2010 until March 2021. In March 2021, The Ohio History Connection took back active management of the site. Following an instance of vandalism in 2015, more security cameras and protective gates were added to ensure the protection of the site and surrounding area.


Gorgets and points from the Adena culture, found at Serpent Mound
Gorgets and points from the Adena culture, found at Serpent Mound
Hopewell pipe, points, and earspool on display at Serpent Mound
Hopewell pipe, points, and earspool on display at Serpent Mound

During excavation of The Serpent Mound archaeologists uncovered pipes, points, and earspool from the Hopewell culture as well as Gorgets and points from the Adena culture.

After raising sufficient funds, Putnam returned to the same site in 1886. He worked for four years to excavate the burial sequence contents of both The Serpent Mound and two nearby conical mounds. After completing his excavation and publishing his work, Putnam worked on restoring the mounds to their original state.

One of the conical mounds that was excavated by Putnam in 1890 yielded several artifacts of a principal burial hosted by during the period of the Adena people. Along with these findings, Putnam found and excavated nine intrusive burials in the mound through his discovery of an ash bed containing many prehistoric artifacts, north of the conical mound. After the excavation, the conical mound was reconstructed and currently stands just south of the parking lot at The Serpent Mound State Memorial.[16]

In 2011, archaeologists took the opportunity to excavate the property prior to installation of utility lines at The Serpent Mound State Memorial. The excavations focused on three sides of the conical mound which had previously been excavated by Putnam in 1890. In addition to these concentrations of artifacts, an ashy soil horizon was excavated north of the conical mound, where archaeologists were able to uncover many prehistoric artifacts. It is believed that the ashy deposit of charcoal is the remainder of a Fort Ancient Culture ash bed. The wood charcoal from within the remnant bed was carbon dated back to the time of the Fort Ancient Culture, between the years of 1041 A.D. and 1211 A.D. Given the results found through carbon dating, burials in the conical mound dated to the Early Woodland and Fort Ancient periods, suggestive of ritual reuse of the circum mound area and ash bed.[16]

Serpent Mound Museum

Main article: Ohio Historical Society

Digital Geographic Information System Map of The Serpent Mound
Digital Geographic Information System Map of The Serpent Mound

In 1901, the Ohio Historical Society hired engineer, Clinton Cowan, to survey newly acquired lands. Cowan created a 56 by 72-inch (1,800 mm) map that depicted the outline of The Serpent Mound in relation to nearby landmarks, such as hills and rivers. Along with this, Cowan made specific geographical surveys of the area, discovering a unique astrobleme on which the mound is based. He found that the mound is at the convergence of three distinctly different soil types. Cowan's information, in conjunction with Putnam's archaeological discoveries, has been the basis for all modern investigations of The Serpent Mound. Furthermore, a digital GIS map of Ohio's Great Serpent Mound was created by Timothy A. Price and Nichole I. Stump in March 2002.

In 1967, The Ohio Historical Society opened The Serpent Mound Museum, built very close to the site of the mound. A pathway was constructed around the base of the mound, guiding visitors through and around the site. The museum features exhibits that include explanations of the effigy's form, description of the constructing of the mound and the geographical history of the area. The museum also features an exhibit on the Adena culture, which they historically credited as the creators of the mound.

Serpent Mound State Memorial is currently being operated on behalf of the Ohio Historical Society by the Arc of Appalachia Preserve System. It is a non-profit organization that specializes in the preservation and protection of native biodiversity and prehistoric aboriginal sites in southern Ohio.

See also


  1. ^ "National Register Information System". National Register of Historic Places. National Park Service. January 23, 2007.
  2. ^ "Serpent Mound". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
  3. ^ "Great Serpent Mound". October 2002. Retrieved 2022-05-03.
  4. ^ "New Radiocarbon Dates Suggest Serpent Mound is More Than 2,000 Years Old - The Ancient Earthworks Project". 2017-03-27. Archived from the original on 27 March 2017. Retrieved 2022-04-26.
  5. ^ Herrmann, Edward W., G. William Monaghan, William F. Romain, Timothy M. Schilling, Jarrod Burks, Karen L. Leone, Matthew P. Purtill, and Alan C. Tonetti (2014), A New Multistage Construction Chronology for the Great Serpent Mound, USA. Journal of Archaeological Science 50:117-125.
  6. ^ Monaghan, G. William; Herrmann, Edward W. (2019-01-01). "Serpent MoundStill Built by the Adena, and Still Rebuilt During the Fort Ancient Period". Midcontinental Journal of Archaeology. 44 (1): 84–93. doi:10.1080/01461109.2018.1511156. ISSN 0146-1109. JSTOR 26599989. S2CID 158652932.
  7. ^ Lepper, Bradley T. (2018-01-02). "On the Age of Serpent Mound: A Reply to Romain and Colleagues". Midcontinental Journal of Archaeology. Informa UK Limited. 43 (1): 62–75. doi:10.1080/01461109.2017.1419917. ISSN 0146-1109. S2CID 165388387.
  8. ^ W. A. Kenyon, Mounds of Sacred Earth - Burial Mounds of Ontario. Royal Ontario Museum, 1986. ROM Archaeology Monograph 9. ISBN 0-88854-303-4
  9. ^ World’s most-complete mastodon debuts in science center.
  10. ^ "Shelby County Historical Society - Indians - About the Paleo-Indians". Retrieved 2022-04-26.
  11. ^ a b Lepper, Bradley T.; Frolking, Tod A.; Pickard, William H. (2019-01-02). "Debating the Age of Serpent Mound: A Reply to Romain and Herrmann's Rejoinder to Lepper Concerning Serpent Mound". Midcontinental Journal of Archaeology. 44 (1): 42–56. doi:10.1080/01461109.2018.1507806. ISSN 0146-1109. S2CID 165322960.
  12. ^ "Adena culture - Ohio History Central". Retrieved 2022-04-26.
  13. ^ "American Indians - Ohio History Central". Retrieved 2022-04-26.
  14. ^ Webb, William S. (2001). The Adena people. University of Tennessee Press. hdl:2027/heb.03744. ISBN 978-0-87049-159-7.
  15. ^ a b c "Serpent Mound: A Fort Ancient Icon?", Midcontinental Journal of Archaeology, Vol. 21, No.1, University of Iowa, 1996
  16. ^ a b Schwarz, Kevin. "Long Shadows Over the Valley: Recent Findings from ASC Group's Excavations at Serpent Mound State Memor". ((cite journal)): Cite journal requires |journal= (help)

Further reading