The Old Copper complex, also known as the Old Copper culture, is an ancient culture from the early period of North America's Great Lakes region. Artifacts found at these sites have been dated to between 6500 and 1580 BCE. This culture is known for creating many copper items, such as tools, weapons, and decorative objects.

Western Great Lakes

The Old Copper complex of the Western Great Lakes is the most well-known and dates back to about 6,500 BCE. People living in the Archaic period near the Great Lakes found 99% pure copper near Lake Superior. This copper was found in surface veins and in nuggets within gravel beds. Major copper mining areas were located on Isle Royale, the Keweenaw Peninsula, and the Brule River. Glaciation also spread copper to other locations.

These cultures shaped copper by heating, annealing, and hammering it. They made tools, spearpoints, and decorative objects from the copper. They used copper for their own needs and also traded it for other valuable materials. By about 1,000 BCE, copper was mostly used for jewelry and items that showed social status, rather than for tools. This change is believed to reflect the growth of more complex social structures in the region.

The Copper Culture State Park in Oconto, northeastern Wisconsin, contains an ancient burial ground used by the Old Copper complex culture between about 4,000 and 2,000 BCE. The site was rediscovered in June 1952 when a 13-year-old boy found human bones while playing in an old quarry. By July, the Wisconsin Archaeological Survey began the first archaeological dig at the site.