In 1885, concerned citizens, historians, and archaeologists formed the Ohio Archaeological and Historical Society, now the Ohio Historical Society, to conserve Ohio's rich cultural resources after long neglect of the state's prehistoric remains. The Society championed the conservation of Hopewell culture sites, conducted many archaeological investigations there, and pressed for the creation of Mound City Group National Monument and ultimately Hopewell Culture National Historical Park, of which Seip Earthworks is a part, managed cooperatively with the National Park Service. The Society maintains one of the nation's most significant collections of prehistoric Indian artifacts at the Ohio Historical Center in Columbus and, as a private nonprofit serving as Ohio's agent in historical matters, it interprets, collects, and preserves the state's heritage. It identifies and monitors Ohio's historic places and archaeological sites, with 42,682 prehistoric sites recorded as of May 2007, and as one of the nation's largest state historical organizations it manages the state archives, administers the historic preservation office, and operates a network of historic sites and museums. William C. Mills, curator of the Ohio Archaeological and Historical Society, excavated at Seip Mound with his team in 1906 and was responsible for proposing Mound City as a national park site.