- a river in SE Canada, flowing northeast from Lake Ontario, forming part of the border between Canada and the US, to the Gulf of St Lawrence: commercially one of the most important rivers in the world as the easternmost link of the St Lawrence Seaway. Length: 1207 km (750 miles). Width at mouth: 145 km (90 miles)
- a deep arm of the Atlantic off the E coast of Canada between Newfoundland and the mainland coasts of Quebec, New Brunswick, and Nova Scotia
