Total maritime tonnage at the Port of Duluth-Superior in 2023 increased 4.5% over the previous year, helped along by more than 21.5 million tons of iron ore — the most shipped in a single season since 1995, according to the port authority.

Iron ore was up 12.6% from 2022, with increases in both domestic shipping and exports. Last month, the season closed with more than a million tons of iron ore shipped from Duluth-Superior, the highest amount for a January since the start of electronic record keeping in 2003.

The total float was more than 31.7 million short tons, with season-over-season increases in eight cargo categories, including cement, grain and durum wheat, the Duluth Seaway Port Authority said in its annual season recap. With the start of a partnership between Duluth Cargo Connect and the Netherlands-based Spliethoff, containerized general cargo tonnage quadrupled from the previous year.

Deb DeLuca, executive director of the Duluth Seaway Port Authority, called it a "very good season for our port" in a news release.

The international shipping season was 277 days, the longest in port history. It started with the arrival of Federal Dart on March 28, 2023, the earliest oceangoing ship on record, and ended with Nordika Desgagnes, which left on Dec. 29. A total of 775 vessels came through Duluth-Superior, the most since 2018.

The Great Lakes navigation season lasted 305 days — also among the longest in history.