city, seat of St. Louis county, northeastern Minnesota, U.S. One of Minnesota's largest cities, it is a major inland port on the western tip of Lake Superior (Superior, Lake), at the mouth of the St. Louis River, opposite Superior, Wisconsin. Elevation is abrupt, rising 600 feet (180 metres) above the level of the lake in high rock bluffs, once the shoreline of glacial Lake Duluth. Along the crest a 30-mile (50-km) skyline boulevard commands an excellent view of both city and harbour. The combined Duluth-Superior harbour results from a natural breakwater formed by deposits left where river and lake meet. This resulting 9-mile (14-km) strip, Minnesota Point, or Park Point, extends toward Wisconsin Point, separating St. Louis and Allouez bays from Lake Superior. The narrow channel between the two points forms the Superior harbour entrance, and a dredged 300-foot (90-metre) ship canal across Minnesota Point, spanned by an aerial lift bridge, forms the Duluth harbour entrance. The combined harbour is the western terminus of the St. Lawrence Seaway (Saint Lawrence River and Seaway), and, although icebound during the winter months, it is the largest port on the Great Lakes and one of the largest inland seaports in the world. Among the items shipped through it are iron ore from the Mesabi Range, coal from the western United States, and grain from the Red River valley and Canada. Harbour facilities include coal docks, grain elevators, and iron ore docks (which receive taconite from processing plants in northeastern Minnesota).

The area, occupied originally by the Sioux and the Ojibwa, was visited in the 17th century by French voyageurs, including Daniel Greysolon, sieur DuLhut (DuLhut, Daniel Greysolon, Sieur) (or Du Luth), who claimed the area for France in 1679 and for whom Duluth was named. The fur-trading post of Fond du Lac, on the St. Louis River, was active until the mid-19th century and was controlled successively by the Hudson's Bay Company, the North West Company, and the American Fur Company. In 1852 the first settler, George P. Stuntz, arrived. Settlers in search of copper deposits arrived the following year, and Duluth was laid out in 1856. Railway extension into the northwestern wheat region, increased lake commerce following the cutting of the Duluth Ship Canal in 1871, lumbering, and development of the iron ranges brought increasing prosperity.

Duluth is a regional health care, business, retail, education, financial, and cultural centre for northeastern Minnesota and northwestern Wisconsin. In addition to shipping, economic assets include the railroads, an oil pipeline from Canada, a military air-defense installation at Duluth International Airport, aircraft maintenance facilities, government offices, the tourism industry, and paper milling, food processing, and printing and publishing enterprises. It is the site of a campus of the University of Minnesota (Minnesota, University of) (established in 1895, joined system in 1947) and the College of St. Scholastica (1912; affiliated with the Roman Catholic church), as well as a community college (1995).

Duluth's cultural activities include a symphony orchestra, ballet, and playhouse, as well as the Duluth Art Institute and the Tweed Museum of Art. The Lake Superior Railroad Museum and the Lake Superior Maritime Visitor Center preserve the area's railroading and shipping history. Great Lakes Aquarium is the only all-freshwater aquarium in the United States. Glensheen (1908) is a 22-acre (9-hectare) lakeside estate. Clayton Jackson McGhie Memorial (dedicated 2003) commemorates three African Americans murdered in the city. Duluth also features a zoo and a ski resort. The John Beargrease Sled Dog Marathon, held each February, is a round-trip race up the lakeshore to Grand Marais. Jay Cooke State Park is just southwest of the city, and the Fond du Lac Ojibwa reservation is a few miles west. Duluth is the headquarters of Superior National Forest. Inc. 1870; re-inc. 1887. Pop. (1990) city, 85,493; Duluth-Superior MSA, 239,971; (2000) city, 86,918; Duluth-Superior MSA, 243,815.