Cultures of indigenous peoples lived along the river valleys for thousands of years before European contact. From more than two thousand years ago, 100 AD to 500 AD, people of the Hopewell culture transformed the area of Newark and Heath. They built many earthen mounds and enclosures, creating the single largest earthwork complex in the Ohio River Valley. The Newark Earthworks, designated a National Historic Landmark, have been preserved to document and interpret the area's significant ancient history. The earthworks cover several square miles and about 206 acres. This is operated as a state park by the Ohio History Connection.