The Beauharnois Canal (, ) is located in southwestern Quebec, Canada. The canal is part of the Saint Lawrence Seaway.
Located in Beauharnois-Salaberry Regional County Municipality within the cities of Salaberry-de-Valleyfield, Beauharnois, Saint-Louis-de-Gonzague, and Saint-Stanislas-de-Kostka, the canal connects Lake Saint-Francis to the west (upstream) with Lake Saint-Louis to the northeast (downstream), bypassing a series of rapids on the Saint Lawrence River.
History
thumb|left|Construction on Beauharnois Canal in 1930
The original Beauharnois Canal opened in 1843, and measured in length and was built on the south side of the St. Lawrence River. It replaced the Coteau-du-Lac canal.
The canal became obsolete and was superseded by the Soulanges Canal in 1899 which ran on the north side of the St. Lawrence River.
The present Beauharnois Canal was built between 1929-1932 on the south side of the St. Lawrence River, measuring in length, with a minimum depth of and width of .