St. Lawrence River

The St. Lawrence River (French: Fleuve Saint-Laurent, pronounced [flœv sɛ̃ lɔʁɑ̃]) is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean. Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawrence, traversing Ontario and Quebec in Canada and New York in the United States. A section of the river demarcates the Canada–U.S. border.

As the primary drainage outflow of the Great Lakes Basin, the St. Lawrence has the second-highest discharge of any river in North America (after the Mississippi River) and the 16th-highest in the world. The estuary of the St. Lawrence is often cited by scientists as the largest in the world. Significant natural landmarks of the river and estuary include the 1,864 river islands of the Thousand Islands, the endangered whales of Saguenay–St. Lawrence Marine Park, and the limestone monoliths of the Mingan Archipelago.

Long a transportation route to Indigenous peoples, the St. Lawrence River has played a key role in the history of Canada and in the development of cities such as Montreal and Quebec City. The river remains an important shipping route as the backbone of the St. Lawrence Seaway, a lock and canal system that enables world marine traffic to access the inland ports of the Great Lakes Waterway.

The river has historically been given a variety of different names by local First Nations. Beginning in the 16th century, French explorers visited what is now Canada and gave the river names such as the Grand fleuve de Hochelaga and the Grande rivière du Canada, where fleuve and rivière are two French words (fleuve being a river that flows into the sea).

The river's present name has been used since 1604 when it was recorded on a map by Samuel de Champlain. Champlain opted for the names Grande riviere de sainct Laurens and Fleuve sainct Laurens in his writings, supplanting the earlier names. In contemporary French, the name is rendered as the fleuve Saint-Laurent. The name Saint-Laurent (Saint Lawrence) was originally applied to the eponymous bay by Jacques Cartier upon his arrival into the region on the 10th of August feast day for Saint Lawrence in 1535.

Indigenous people use the following names:

In winter, the St. Lawrence River begins producing ice in December between Montreal and Quebec City. The prevailing winds and currents push this ice towards the estuary, and it reaches the east of Les Méchins at the end of December. Ice covers the entire Gulf of St. Lawrence in January and February.

Ice helps navigation by preventing the formation of waves, and therefore spray, and prevents the icing of ships.