Delson is an off-island suburb (South shore) of Montreal, Quebec, Canada. It is situated 8 mi/13 km SSE of Montreal within the regional county municipality of Roussillon in the administrative region of Montérégie. The population as of the Canada 2021 Census was 8,328.
On its small territory, Delson is crossed by Route 132 and the Turtle River (Rivière de la Tortue). The city owns a portion of the Champlain industrial park as well as the Delson commuter train station with service to and from Montreal on the AMT's Candiac Line.
The origin of the name Delson comes from the Delaware and Hudson Railway, now a subsidiary of the Canadian Pacific Railway, which runs through the town. The Canadian Railway Museum (Exporail) occupies a large tract between Delson and Saint-Constant.
Delson was founded in 1918 as a village municipality before obtaining its status of a city 21 February 1957. The village of Delson was created from three parishes: St Andrews (1924) of the United Church and St David (1938) of the Anglican church, as well as Sainte-Thérèse-de-l'Enfant-Jésus (1932) of the Catholic faith.
The city lies along the south shore of the Saint Lawrence River, south of the island of Montreal.
The following waterways pass through or are situated within the municipality's boundaries:
In the 2021 Census of Population conducted by Statistics Canada, Delson had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of , it had a population density of in 2021.
Delson is the hometown of retired NHL goalie Marcel Cousineau.