The first settlers in the Enon, Ohio, area were the Adena Native Americans, known for mounds like the Enon mound. Adena, Hopewell, and Fort Ancient cultures developed earthworks in much of Ohio from circa 52 BC to 1500 AD, and the Shawnee later moved into the area, with one village north of Enon where George Rogers Clark Historical Park is located. According to legend, General Clark's troops climbed the Enon mound to reconnoiter the area while looking for Shawnee. It is said that in the 19th century young men dug into the mound and found a room of rock at the bottom, but nothing else was found. The mound stood on what was later known as Knob Prairie Mound Farm, and in the early 1900's it became the center of a large dirt racetrack. Covering over one acre, measuring 574 feet in circumference, and rising 40 feet high, it is the second tallest conical mound in Ohio; only Miamisburg Mound in Miamisburg, Ohio, is taller at 65 feet. Its construction took about one million trips carrying baskets of soil from the riverbed.