What is the longest river in Canada?

The Mackenzie River is recognized as the longest river in Canada. It spans approximately 4,241 kilometers (about 2,635 miles) and flows through the Northwest Territories, draining into the Arctic Ocean. The significance of the Mackenzie River goes beyond its length; it is an essential waterway for the regions it traverses, supporting ecological diversity and providing transportation routes for Indigenous communities and others.

Comparatively, while the Fraser River and the St. Lawrence River are important in their own right, they are shorter. The Fraser River measures around 1,375 kilometers (about 850 miles), and the St. Lawrence River is about 1,197 kilometers (approximately 742 miles) long. The Ottawa River also is shorter than the Mackenzie at about 1,271 kilometers (around 790 miles). Thus, the choice of the Mackenzie River as the longest river emphasizes its prominence in Canada’s geography and ecology.