Saint Lawrence Seaway

The St. Lawrence Seaway is the common name for a system of canals that permits ocean-going vessels to travel from the Atlantic Ocean to the Great Lakes as far as Lake Superior. Legally it extends from Montreal to Lake Erie, including the Welland Canal and the Great Lakes Waterway. The seaway is named after the Saint Lawrence River, which it follows from Lake Ontario to the Atlantic Ocean.
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Noun
1. a seaway involving the Saint Lawrence River and the Great Lakes that was developed jointly by Canada and the United States; oceangoing ships can travel as far west as Lake Superior
(synonym) St. Lawrence Seaway
(hypernym) seaway, sea lane, ship route, trade route