Duluth is a port city in the U.S. state of Minnesota and serves as the county seat of St. Louis County. Located on the north shore of Lake Superior within Minnesota's Arrowhead Region, it occupies the westernmost point of the Great Lakes. The city sits south of the Iron Range and the Boundary Waters Canoe Area Wilderness, forming a metropolitan area with neighboring Superior, Wisconsin, known collectively as the Twin Ports.

The area was first explored by Europeans in the 17th century, with Daniel Greysolon, Sieur du Lhut, exploring the St. Louis River in 1679. The city is named after him, and its name is sometimes anglicized as DuLuth. Early development centered on the fur trade, followed by timber harvesting and iron ore mining. Thomas Preston Foster coined the expression "The Zenith City of the Unsalted Seas" in 1868, a nickname that reflects the city's rapid growth during the railroad and mining booms.

Built largely on a 700-foot hill overlooking Lake Superior, Duluth features Canal Park and Superior Street as hubs for tourist destinations. The Aerial Lift Bridge crosses the Duluth Ship Canal into the harbor, while Minnesota Point, locally known as Park Point, is the world's longest freshwater baymouth bar. The city is often likened to San Francisco due to its hills, bridges, and bay, with historic mansions in the east end reflecting its past wealth from shipping and milling.

A popular Midwest tourist destination, Duluth offers the Great Lakes Aquarium and serves as the starting point for road trips along the North Shore of Lake Superior. The city hosts the annual Grandma's Marathon, named after a local restaurant in Canal Park. Its thriving tourism industry includes antique shops, excellent restaurants, and scenic views, drawing visitors to its ski resort within city limits and its status as the western endpoint of the scenic North Shore Drive.

The population was 86,697 at the 2020 census, making it Minnesota's fifth-largest city. The economy is driven by cargo shipping through the Port of Duluth, the world's farthest inland port accessible to oceangoing ships, which handles coal, iron ore, and grain. Summer heat indices average around 79 °F, while winter air temperatures generally do not drop below -20°F, though windchills can be bitter.