Lachine is a former city on the Island of Montreal in southwestern Quebec, Canada. It is now a borough (arrondissement) within the city of Montreal. The borough is located in the southwest portion of the island of Montreal, at the inlet of the Lachine Canal, between the borough of LaSalle, and the city of Dorval. It was a separate city until municipal mergers on January 1, 2002 and did not demerge on January 1, 2006. The borough is bordered to the northwest by the city of Dorval to the northeast by Saint-Laurent, to the east by Côte Saint-Luc, Montreal West and a narrow salient of Le Sud-Ouest, and to the south by LaSalle. Its western limit is the shore of Lac Saint-Louis and the Saint Lawrence River. It has an area of 17.83 km² and a population of 41,391.