Great Lakes Waterway River between Huron and Erie. Usually, one or more U.S. Coast Guard icebreakers help keep the water passage open for part of the fall and early winter, although shipping usually ceases for two to three months thereafter. The Great Lakes Waterway is co-administered by the governments of Canada and the United States of America. The waterway allows passage from the Atlantic Ocean to the inland port of Duluth on Lake Superior, a distance of and to Chicago, on Lake Michigan, at . Together with the Saint Lawrence Seaway, the Waterway allows both ocean-going vessels and the ore, grain and coal-bearing
Lake Duluth not been determined. It is known, however, that the lake extended at least to the Kaministiquia River basin west of Fort William, Ontario. It is probable that there was a protrusion of the ice into Keweenaw Bay at the time of greatest expansion of Lake Duluth, and the east end of the Keweenaw Peninsula may have been beneath the ice down to the time the Lake Duluth waters were drained eastward. Glacial Lakes in the Lake Superior basin Lake Duluth Lake Duluth was a proglacial lake that formed in the Lake Superior drainage basin as the Laurentide ice sheet retreated.