 This is thought to represent the development of more complex hierarchical cultures in the area.The Copper Culture State Park, in Oconto, northeastern Wisconsin contains an ancient burial ground used by the Old Copper Complex Culture of early Native Americans, here between 5,000 and 6,000 years ago.It was rediscovered in June 1952 by a 13-year-old boy who unearthed human bones while playing in an old quarry.