Located high on a limestone bluff overlooking the Little Maquoketa River, 32 burial mounds of the Late Woodland people dating back to A D 500-1500, rest peacefully within a protective fence. Late Woodland people of the pre-historic Hopewell Culture built mounds for religious and ceremonial, burial, and elite residential purposes. It is estimated that 10,000 bushels of earth were moved into the area to construct the mounds. Some mounds are 42 feet across and others 50 feet high. The mound area features a mature forest and a segment of a native bluff top prairie. The 42-acre grave site became a state archaeological and geological preserve in 1981. Over 15 Native American tribes were consulted during its development. Information about the site is located at the parking lot and bluff top.