St. Lawrence River

The St. Lawrence River is a massive international waterway in North America.

It serves as the primary drainage outflow for the Great Lakes Basin. This connection allows water to flow from the Great Lakes into the North Atlantic Ocean. The river flows in a northeasterly direction. It starts at the outflow of Lake Ontario. From there, it travels through Ontario and Quebec in Canada. It also passes through New York in the United States. Parts of the river act as the official border between Canada and the U.S.

The river's massive scale is defined by its discharge, which is the volume of water flowing past a point. The St. Lawrence has the second-highest discharge in North America. Only the Mississippi River carries more water. Globally, it ranks as the 16th-highest river by discharge. Its drainage area is vast, covering 1,880,000 square kilometers. This basin includes parts of several U.S. states like Minnesota, Wisconsin, and Michigan. It also covers large portions of Ontario and Quebec. The river's journey includes several large lakes. It flows through Lake Saint-Louis and Lake Saint-Pierre.

Geologically, the river has a fascinating origin story. It formed following the draining of the Champlain Sea. This sea existed from about 13,000 to 10,000 years ago. The sea shrank as the continent rebounded after the Last Glacial Maximum. The river also sits in a seismically active zone. This means there is a risk of earthquakes. This activity is related to the Saint Lawrence rift system. These are faults linked to the opening of the ancient Iapetus Ocean. The river valley is part of the Appalachian division in the U.S. However, in Canada, it is part of the St. Lawrence Lowlands.

Indigenous peoples have used the river for transportation for a very long time. Because the river crosses many lakes, it has many different names. The Algonquin called it Magtogoek, or "the Walking Path." The Mohawk used names like Roiatatokenti or Ken’tarókwen. The Wendat Nation called it Lada8anna. European explorers arrived later in the 16th century. Jacques Cartier arrived in 1535. He named the region after the feast day of Saint Lawrence. In 1604, Samuel de Champlain mapped the river. He recorded names like Fleuve sainct Laurens.

The river is home to an incredible amount of biodiversity. The estuary and gulf support 2,200 different invertebrates. These include species like jellyfish, corals, and crustaceans. There are 19 species of marine mammals living in these waters. You can find endangered whales in the Saguenay–St. Lawrence Marine Park.

More than 230 species of birds use the river. There are also nearly 2,000 types of vascular plants. The water holds 200 species of fish. This list includes 19 different types of sharks and rays. The river also contains beautiful natural landmarks. These include the 1,864 islands of the Thousand Islands. You can also find the limestone monoliths of the Mingan Archipelago.

Modern technology allows large ships to use the river as a major shipping route. This is made possible by the St. Lawrence Seaway. The Seaway is a system of locks and canals. Locks allow ships to move between different water levels. This system connects the Great Lakes Waterway to world marine traffic. The river also undergoes seasonal changes. In December, ice begins to form near Montreal and Quebec City. The winds and currents push this ice toward the estuary. By January, ice covers the entire Gulf of St. Lawrence. Interestingly, this ice can help navigation. It prevents waves and spray from icing up the ships.