Duluth, Minnesota at the western end of the Saint Lawrence Seaway, the Duluth–Superior seaport is the largest and farthest-inland freshwater seaport in North America. By far the largest and busiest on the Great Lakes, the port handles an average of 46 million short tons of cargo and over 1,100 visits each year from domestic and international vessels. With of waterfront, it is one of the leading bulk cargo ports in North America and ranks among the top 20 ports in the United States. Duluth is a major shipping port for taconite pellets, made from concentrated low-grade iron ore and destined for midwestern
Proglacial lakes of Minnesota The lake bed is now a sandy and clayey plain. It is also a source for reed-sedge peat, which is harvested, processed, and packaged for agricultural applications; it enables plants to fix nitrogen and thereby reduces the need for fertilizer. The company harvesting the peat and the University of Minnesota-Duluth are developing processes to use the peat to extract mercury and other heavy metals, and also to remove sulfates from water by a method which enables the peat to be reused. Glacial Lake Duluth is the name given to the largest of a series of named lakes or lake stages