Tremper Mound is one of the best-preserved examples of a Hopewell Culture (100 B.C. to 500 A.D.) burial mound. Like many other earthworks and mounds, this site is in close proximity to a river and is located on a bluff which overlooks the Scioto River. There has been debate about whether this particular mound should be considered an animal effigy mound, known as a zoomorphic geoglyph, because of its unique shape, or whether this was a burial mound because of its use and contents. The history of the mound and the artifacts removed from it are displayed at the Ohio History Center in Columbus, Ohio.
This particular ancient work is both a mound and an earthwork, or rather an earthwork containing a possible animal effigy mound. The earthwork consists of an almost elliptical enclosure, the longest axis being 480 feet, and its conjugate diameter measuring 407 feet. The embankment was approximately three feet high and had a base width of thirty feet when it was surveyed in 1846. The oval is incomplete having a gateway in the south-eastern area measuring approximately 90 feet wide. There is a second small embankment that seems to guard the gateway and matches the three-foot height of the large embankment.
The interior of the embankment houses an oddly shaped mound that was excavated by the Ohio Historical Society. The original survey from 1846 has the mound at a height ranging from 1-8 feet with the smaller heights located at what would be considered the head and the four points of the legs. The 1915 excavation measured the mound at 250 feet in length, 120 feet wide, with a height of 5 feet. The shape of the mound has been compared to similar mounds found in Wisconsin.
Its irregular shape has been attributed to the structure contained within. This mound consists of a charnel house with multiple partitions. A charnel house is a place built with the specific intent of interring the remains of the dead. It has been found that burial mounds were built in sections with the main burial relating to a very important person, and as other celebrated individuals passed, the mound would be added to over time changing its shape or adding height in the case of many conical mounds.
Other burial mounds built by the same culture usually contain multiple burials with the individuals being separated and contained in a form of log tomb. This mound differs greatly not only in shape but also in the way remains were interred. Two people are buried in graves beneath the floor of the main burial chambers. It is assumed that these were the first burials. The main structure is divided into five burial depositories and contains twelve crematory basins. Approximately 375 persons were cremated using these basins and then interred in four of the depositories with one standing empty.
There was also an extraordinary amount of artifacts within the mound. One of the eastern chambers contained 500 objects which had been deliberately broken. It contained ninety animal effigy pipes, some carved into birds including waterfowl like herons, cranes and even predatory birds like owls and hawks. Other pipes were shaped like turtles, otters, beavers, bears, and wolves. The pipes were made of catlinite known as pipestone. Testing has revealed that some of the stone was quarried locally while other pipes were made of Sterling pipestone that hails from northwestern Illinois. This again shows the long stretching trade route that had been established or continued by the Hopewell Culture. The Hopewell Culture is remembered for its geometric earthworks and their trade of materials from across North America including obsidian, copper, mica, and marine shell used to create funerary and other useful items.