Final answer:
The Gulf of St. Lawrence is east of the St. Lawrence River, flowing from Quebec and opening into the Atlantic Ocean west of the Canadian Maritimes.
Step-by-step explanation:
The Gulf of St. Lawrence is located east of the St. Lawrence River. This gulf is a very large estuary in eastern Canada and the outlet of North America's Great Lakes via the Saint Lawrence River into the Atlantic Ocean. Starting in Quebec, the St. Lawrence River flows northeast and widens into the Gulf, ultimately opening into the Atlantic Ocean east of Quebec and west of the Canadian Maritimes. French Canada, particularly Quebec, has a rich history connected to the St. Lawrence River as it was an important region during colonization by France and later Great Britain.