Longueuil, city, Chambly County, southern Québec, Canada, on the St. Lawrence River. It is a residential and industrial community opposite Montréal, to which it is connected by bridge and subway. Major manufactures include aircraft equipment, machinery, metal products, food products, and furniture. A branch campus of the Université de Sherbrooke is located in Longueuil. The city is the site of the Regional Park of Longueuil, the Jacques Ferron Cultural Center, and the historic Saint Antoine's Church.
The community was settled in 1657 by Charles Le Moyne, Sieur de Longueuil et Châteauguay, and named after his mother's birthplace in France. It grew as a transportation center after the mid-19th century and incorporated as a city in 1920. The municipality of South Montréal annexed itself to Longueuil in 1961, and in 1969 the city of Jacques Cartier merged with Longueuil.
