In the 1840s, Charles W. Whittlesey, while working as the Assistant Geologist of Ohio, created the first survey of what would become known as Tremper Mound. Located on the westside of the Scioto River, a few miles from Portsmouth, Tremper Mound is considered part of the larger complex of mounds and earthworks at Portsmouth. Whittlesey’s Map would be included by Squier and Davis in their publication, Ancient Monuments of the Mississippi Valley (1848). Based upon Whittlesey's survey work, Squier and Davis concluded that Tremper Mound was designed as an “animal effigy” mound, but following its excavation in 1915, archeologists have generally concluded that the shape was not intended as an effigy. Rather, its shape is a result of the footprint of a structure with wood posts, which was then covered by the mound construction.