Duluth, Minnesota Lakes Waterway and the Saint Lawrence Seaway. Duluth forms a metropolitan area with neighboring Superior, Wisconsin, called the Twin Ports. The cities share the Duluth–Superior harbor and together are the Great Lakes' largest port, transporting coal, iron ore (taconite), and grain. A tourist destination for the Midwest, Duluth features the United States' only all-freshwater aquarium, the Great Lakes Aquarium; the Aerial Lift Bridge, which spans the Duluth Ship Canal into the Duluth–Superior Harbor; and Minnesota Point (known locally as Park Point), the world's longest freshwater baymouth bar, spanning . The city is also the starting point for vehicle trips along
Lake Duluth Lake Duluth Lake Duluth was a proglacial lake that formed in the Lake Superior drainage basin as the Laurentide ice sheet retreated. The oldest existing shorelines were formed after retreat from the Greatlakean advance (previously called the Valders), sometime around 11,000 years B.P. Lake Duluth formed at the western end of the Lake Superior basin. Lake Duluth overflowed south through outlets in Minnesota and Wisconsin at an elevation of around 331 m above sea level. As the Superior lobe of the Laurentian Ice Sheet melted, water became trapped along the ice margin and formed several independent lakes. The modern water