It is the seat of the Montérégie administrative region and the central city of the urban agglomeration of Longueuil.

Longueuil was founded in 1657 by Charles Le Moyne, a merchant from Ville-Marie (present day Montreal), as a seigneurie.

[7] According to Abbé Faillon, Charles Le Moyne, lord of the area starting in 1657, named Longueuil after the village of Longueil (note slightly different spelling) which is today the seat of a canton in the district of Dieppe in his homeland of Normandy.

[8] The archaeological remains of Fort Longueuil were recognized as a National Historic Site of Canada on May 25, 1923.

[8] The seigneurial system ended in 1845 and Longueuil was turned into a parish municipality named Saint-Antoine-de-Longueuil.

On January 1, 2002, as part of the 2000–2006 municipal reorganization in Quebec, the provincial government amalgamated the former Longueuil with Boucherville, Brossard, Greenfield Park, LeMoyne, Saint-Bruno-de-Montarville, Saint-Hubert and Saint-Lambert.

However, after a change of government and a 2004 referendum, Boucherville, Brossard, Saint-Lambert and Saint-Bruno-de-Montarville were re-constituted as independent cities on January 1, 2006.

The city of Longueuil is located approximately 7 kilometres (5 mi) east of Montreal on the south shore of the Saint Lawrence River.

Like Montreal, Longueuil is classified as humid continental or hemiboreal (Köppen climate classification Dfb).

The largest visible minority groups are Black (9.9%), Latin American (4.6%), Arab (4.4%), Chinese (1.7%), Indigenous (1.3%), and West Asian (1.1%).

[22] Although a large portion of Longueuil's work force commutes to Montreal, the city nevertheless offers many jobs in a diverse range of industries.

[30] Other companies based in Longueuil include Agropur, Innergex Renewable Energy, and the Canadian subsidiary of Hasbro.

[31][32] In 2002 Artemano Canada, a home furnishing company was founded, with warehouse & distribution centre located in Longueuil.

Greenfield Park has three councillors and its borough president is Mireille Carrière of Action Longueuil.

Le Vieux-Longueuil has fifteen councillors and its borough president is Michel Desjardins of the Parti municipal de Longueuil.

The electoral district of Laporte includes the boroughs of Greenfield Park and Saint-Hubert, and is represented by Nicole Ménard of the Quebec Liberal Party.

The electoral district of Marie-Victorin, which includes the western portion of Le Vieux-Longueuil, is represented by Catherine Fournier of the Parti Québécois (PQ).

The electoral district of Taillon, which covers the eastern portion of Le Vieux-Longueuil is represented by Marie Malavoy of the PQ.

The electoral district of Vachon, which covers the borough of Saint-Hubert, is represented by Martine Ouellet of the PQ.

[41] The Saint Lawrence River between the Island of Montreal and the south shore is traversed by only five automobile crossings.

Route 116 is another major highway, with its western terminus located in LeMoyne, heading east through the borough of Saint-Hubert toward Saint-Bruno-de-Montarville.

Prior to the opening of the REM South Shore branch, many buses normally terminating at Panama station crossed the Champlain Bridge during peak hours to arrive at the Terminus Centre-Ville in downtown Montreal (under the 1000 de la Gauchetière office tower, at Bonaventure Metro).

The Réseau de transport métropolitain (RTM) runs the Mont-Saint-Hilaire commuter train line also serves the south shore.

Until the mid-1950s, Longueuil was served by interurban streetcars operated by the Montreal and Southern Counties Railway.

Prior to 1998 the South Shore Protestant Regional School Board served the municipality.

Both "Le Courrier du Sud" and "Rive-Sud Express" are both home delivered as well as available in newspaper boxes.

Another radio station, CHMP-FM 98.5 is officially licensed to Longueuil, despite both the studio and transmitter being located in Montreal.

Residents of Longueuil and adjacent communities are also served by a local cable television station, Télé Rive-Sud (TVRS), which is owned by Quebecor Media and is an affiliate of Canal Vox.