The Lachine Canal is a canal passing through the southwestern part of the Island of Montreal, Quebec, Canada, running 14.5 kilometres from the Old Port of Montreal to Lake Saint-Louis, through the boroughs of Lachine, Lasalle and Sud-Ouest. Before the canal construction there was a lake, "Lac St Pierre". The lake and its rivers can be seen on the maps of Montreal of the years 1700, and on the map titled "The isles of Montreal. As they have been surveyed by the french engineers" (1761).