Duluth/dəˈluːθ/ is a seaport city in the U.S. state of Minnesota and the county seat of Saint Louis County. Duluth has a population of 86,110 and is the second-largest city on Lake Superior's shores, after Thunder Bay, Ontario, on the lake's Canadian border; it does, however, have the largest metropolitan area on the lake. The Duluth MSA had a population of 279,771 in 2010, the second-largest in Minnesota. The combined urban population of Duluth and its adjacent communities – including Proctor, Hermantown, and Superior, Wisconsin – totals over 131,000, based on 2010 census figures.
Situated at the westernmost point of the Great Lakes on the north shore of Lake Superior, Duluth is accessible to oceangoing vessels from the Atlantic Ocean 2,300 miles (3,700 km) away via the Great Lakes Waterway and the Saint Lawrence Seaway. Lake Superior is the world's largest freshwater lake by surface area.
Duluth forms a metropolitan area with Superior 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 America's 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 6 miles (9.7 km). The city is also the starting point for vehicle trips along Minnesota's North Shore.
The city is named for Daniel Greysolon, Sieur du Lhut, the first known European explorer of the area.