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
Lake Superior adventurers. Lake Superior has been an important link in the Great Lakes Waterway, providing a route for the transportation of iron ore as well as grain and other mined and manufactured materials. Large cargo vessels called lake freighters, as well as smaller ocean-going freighters, transport these commodities across Lake Superior. Because of ice, the Lake is closed to shipping from mid-January to late March. Exact dates for the shipping season vary each year, depending on weather conditions that form and break the ice. The southern shore of Lake Superior between Grand Marais, Michigan, and Whitefish Point is known as the