Visible remnants of Hopewell culture are concentrated in the Scioto River valley near the present-day city of Chillicothe, Ohio. The most striking Hopewell sites contain earthworks in the form of circles, squares, and other geometric shapes. Many of these sites were built to a monumental scale, with earthen walls up to 12 feet high outlining geometric figures more than 1,000 feet across. Conical and loaf-shaped earthen mounds up to 30 feet high are often found in association with the geometric earthworks. Hopewell Culture National Historical Park preserves six earthwork complexes: High Bank Works, Hopeton Earthworks, Hopewell Mound Group, Mound City Group, Seip Earthworks and Spruce Hill Earthworks.