The Saguenay River is a major river of Quebec, Canada. It drains Lac Saint-Jean in the Laurentian Highlands, leaving at Alma and running east, and passes at the city of Saguenay. It drains into the Saint Lawrence River at Tadoussac.
The river has a very high flow rate and is bordered by steep cliffs. Tide waters flow upriver as far as Saguenay (about 100 kilometres). Many Beluga whales breed in the cold waters at its mouth, making Tadoussac a popular site for whale watching. The confluence of the Saguenay and Saint Lawrence is protected by the Saguenay - St. Lawrence Marine Park, one of Canada's national parks.
It was an important trade route into the interior for the First Nations people of the area, and during the French colonization of the Americas was a major route for the fur trade. Tadoussac, France's first trading post in Canada, was established in 1600. The river takes its name from the legendary Kingdom of the Saguenay.
The river was exploited for the logging and pulp and paper industries beginning in the 19th century, and is also used for hydroelectricity generation, both for commercial power and to operate an aluminum smelter at Arvida.