L'Île-Dorval is a city and an island in southwestern Quebec, Canada, in Lac Saint-Louis off the Island of Montreal. It lies a short distance offshore from the city of Dorval and is connected with a seasonal ferry service.
A cottaging spot, it had only 5 permanent residents as of the Canada 2011 Census, making it the smallest municipality in Canada both in area and population. In the 2001 census the official population had dropped to zero, according to Statistics Canada. However, because not only permanent residents but also property owners are eligible to vote in municipal elections in Québec, there were 50 registered voters in 2004.
On January 1, 2002, as part of the 2002–2006 municipal reorganization of Montreal, it merged with the city of Montreal to become part of the borough of Dorval–L'Île-Dorval. After a change of government and a 2004 referendum it became independent once again, effective January 1, 2006.