Whitewater Effigy Mounds Preserve is a park operated by the city of Whitewater, Wisconsin. The 21.5-acre park is located on the west side of the city. It was added to the National Register of Historic Places in 1991. It is one of the largest collections of effigy mounds in the country, 12 to 15 mounds can be found within the park. The mounds were built between 800 A.D. and 1200 A.D. The oldest mounds are geometric shapes, and the more recent ones resemble animal shapes ranging in size from 60 to 300 feet. Studies suggest that these mounds were a gathering place for several Midwestern Native American tribes.