The Twin Ports
The Duluth-Superior harbor--collectively known as the Twin Ports, is the busiest harbor in the Great Lakes. The Twin Ports is also distinguished for being the furthest inland seaport in the world. In 2021, 32.8 million tons of cargo were shipped through the Duluth-Superior harbor by 718 separate vessel visits. Exported cargos include taconite (iron ore pellets), western coal, and grain products. The most common imports are limestone, salt, cement, and wind turbine parts. The harbor is in an ideal location and protected from Lake Superior storms by Minnesota Point, the largest natural sandbar in the world. The Duluth-Superior harbor is split by state lines, the north side being Minnesota while the south side is Wisconsin.
The Duluth Entry was dug in 1871 to increase accessibility for ships to the Duluth docks. Minnesota Point became an island, making it difficult for the residents to get to and from the city. In 1905, the Duluth Aerial Lift Bridge was constructed, allowing vessel and foot traffic through the canal.
The Superior Entry was the original entrance into the harbor. The St. Louis river drained naturally through Wisconsin Point and Minnesota Point. It was dredged deeper to allow access for large cargo vessels. Breakwaters and lighthouses were installed to keep ships safe as they came and went.