As the lumber business ran down with the exploitation of forests, the area became linked to other resource extraction. Freighters carried iron from Duluth, Minnesota, which had been mined in the Mesabi Range, to Ashtabula, Ohio for steel processing. They passed from Lake Superior through Lake Huron and to Lake Erie. Marine City was known as the town on the St. Clair River where the captains of lake freighters lived. Many of these men and their crews worked for the Pittsburgh Steamship Company. Formed in 1901 by US Steel Corporation, it became the largest commercial fleet on the Great Lakes.