Keweenaw (kēˈwĭnô) [key], peninsula, 60 mi (97 km) long, projecting NE from the W Upper Peninsula, NW Mich., into Lake Superior. Portage Lake and a connecting ship canal cut across the middle of the peninsula, converting its upper portion into an island and creating an important waterway. The canal is crossed by a bridge with one of the world's heaviest lift spans. The local area is popular with vacationers. Keweenaw National Historical Park traces the development of copper mining in the Upper Peninsula (see National Parks and Monuments, table).