The Delaware Mine is located off U.S. Highway 41, 12 miles (19 km) in Grant Township, Keweenaw County, south of Copper Harbor, Michigan and is a Keweenaw Heritage Site. The Delaware Copper Mine provides tours of one of the oldest copper mines in the Keweenaw, dating back to 1847. The mine had five shafts, with the deepest reaching 1,400 feet (430 m). The mine is open June through October and offers guided and self-guided tours.