Lake Superior islands include Madeline Island in the state of Wisconsin, Michipicoten Island in the province of Ontario, and Grand Island (the location of the Grand Island National Recreation Area) in the state of Michigan. The larger cities on Lake Superior include the twin ports of Duluth, Minnesota and Superior, Wisconsin; Thunder Bay, Ontario; Marquette, Michigan; and the twin cities of Sault Ste. Marie, Michigan, and Sault Ste. Marie, Ontario. Duluth-Superior, at the western end of Lake Superior, is the most inland point on the St. Lawrence Seaway and the most inland port in the world. Among the scenic places on the
The Great Lakes Group provides linehandling assistance to vessels transiting the United States Army Corps of Engineers-administered and -operated Soo Locks at Sault Ste. Marie, Michigan on the St. Mary's River, the only water connection between Lake Superior and the other Great Lakes. The Soo Locks are located in the St. Mary's Rapids, where the water falls about 21 feet from the level of Lake Superior to the level of the lower lakes. Vessels must transit the Soo Locks en route to the principal ports of Duluth, Minnesota and Thunder Bay, Ontario and outbound to the sea. In 1999 Admiral Towing and Barge Company