Vaudreuil-Soulanges
Regional county municipality
Vaudreuil-Soulanges is at the triangle (centre right) formed west of the confluence of the Ottawa and Saint Lawrence River rivers in this satellite image.
Location in province of Quebec.
Coordinates: 45°21′N 74°13′W / 45.350°N 74.217°W / 45.350; -74.217[1]
Country	Canada
Province	Quebec
Region	Montérégie
Effective	April 14, 1982
County seat	Vaudreuil-Dorion
Government [2]
• Type	Prefecture
• Prefect	Patrick Bousez
Area [2][3]
• Total	1,019.70 km2 (393.71 sq mi)
• Land	855.56 km2 (330.33 sq mi)
Population  (2016)[3]
• Total	149,349
• Density	174.6/km2 (452/sq mi)
• Change 2011-2016	7.2%
• Dwellings	59,474
Time zone	UTC−5 (EST)
• Summer (DST)	UTC−4 (EDT)
Area code(s)	450 and 579
Website	www.mrcvs.ca

Vaudreuil-Soulanges (French pronunciation: [vodʁœj sulɑ̃ʒ]) is a regional county municipality in Quebec, Canada. It is located on a triangular peninsula in the western Montérégie region of Quebec, formed by the confluence of the Ottawa River to the north, and the St. Lawrence River to the south. Ontario is located west of here.

Vaudreuil-Soulanges is part of the St Lawrence Valley. Two million years ago the region was subject to a series of glaciations that covered much of North America. The last in the series was the Wisconsin glaciation. The ice sheet weighed down the landscape. This created the depressions in the land that created the basins for Lake Saint-Louis, Lac des Deux-Montagnes and Lake Saint-Francis. As the ice sheet eroded, the region was mostly submerged 12,000 years ago by an inland saltwater sea known as the Champlain sea. Once the glacier was melted, the land rose again, pushing the saltwater into the sea. 10,000 years ago the body of water, now a fresh water lake, has been named by scholars as Lake Lampsilis.

During the French colonial period, the region of New France was divided into several seigneuries populated by French colonists.^[4]

• Seigneurie de L'Île-Perrot founded on October 29, 1672 (modern day L'Île-Perrot, Pincourt, Notre-Dame-de-L'Île-Perrot and Terrasse-Vaudreuil)^{[5][6][circular reference]}
• Seigneurie de Vaudreuil founded on October 12, 1702 (modern day Vaudreuil-Dorion, Vaudreuil-sur-le-Lac, L'Île-Cadieux, Saint-Lazare and Hudson^{[7][8][circular reference]}
• Seigneurie de Soulanges founded on October 12, 1702 (modern day Saint-Clet, Coteau-du-Lac, Les Cèdres and Pointe-des-Cascades)^{[9][10][circular reference]}
• Seigneurie de Rigaud founded on October 29, 1732 (modern day Rigaud, Sainte-Marthe, Pointe-Fortune and Très-Saint-Rédempteur)^{[11][12][circular reference]}
• Seigneurie de Nouvelle-Longueuil founded on April 21, 1734 (modern day Saint-Polycarpe, Saint-Télesphore, Saint-Zotique, Les Coteaux et Rivière-Beaudette)^{[13][14][circular reference]}
• Canton Newton founded in August 1791 (modern day Sainte-Justine-de-Newton, not part of the seigneurie system, was modeled after British township system)^{[15][16][circular reference]}

The seigneurial system was finally abolished in 1854, nearly a century after Great Britain took over the territory after defeating France in the Seven Years' War.

It is the only county in Quebec that lies both south of the Ottawa River and north of the St. Lawrence River. Great Britain wanted to keep most of the French-speaking, ethnic French population of the area within Lower Canada during the 1791 division of Upper and Lower Canada (precursors to the provinces of Ontario and Quebec). It is geographically isolated from the Montérégie region south of the St. Lawrence.

The name relates to the historical division of the area into two counties: Vaudreuil County -- (named after Pierre François de Rigaud, Marquis de Vaudreuil-Cavagnal, governor of New France) for the communities along the Ottawa River, and Soulanges County -- (named after Pierre-Jacques Joybert de Soulanges from Soulanges, Marne, France) for the communities along the St. Lawrence. Soulanges is a name of Québécois derivation, referring to its southerliness.

Since the RCM formation on 14 April 1982, the division of the county into "Vaudreuil" and "Soulanges" is still salient. The "Vaudreuil" area (consisting of the municipalities of Vaudreuil-Dorion, Saint-Lazare, Hudson, L'Île-Perrot, and others) is closer to Montreal. It is more suburban, populous, and economically and ethnically diverse. By contrast, the Soulanges area (including the municipalities of Saint-Polycarpe, Saint-Zotique, Coteau-du-Lac, Rivière-Beaudette and Les Coteaux) is predominantly rural, agricultural, and ethnically French-Canadian.

Owing to the county's geographic isolation within Quebec, and its growing population as a suburb of the city of Montreal, Elections Canada assigned the electoral district to the county in 1997.

There are 23 subdivisions within the RCM:^[2]

Canada Census Mother Tongue - Vaudreuil-Soulanges Regional County Municipality, Quebec[21][22][3]
Census		Total		French				English				French & English				Other
Year		Responses		Count	Trend	Pop %		Count	Trend	Pop %		Count	Trend	Pop %		Count	Trend	Pop %
2021		161,090		94,820	1.6%	58.87%		37,135	7.1%	23.05%		5,180	84.02%	3.21%		20,640	36.5%	12.81%
2016		148,605		96,365	3.3%	64.85%		32,525	14.17%	21.89%		2,815	14.2%	1.89%		15,120	32.1%	10.17%
2011		137,590		93,300	9.0%	67.81%		30,380	22.7%	22.08%		2,465	62.7%	1.79%		11,445	50.0%	8.32%
2006		119,465		85,565	11.7%	71.62%		24,760	26.2%	20.73%		1,515	18.8%	1.27%		7,625	101.2%	6.38%
2001		101,290		76,610	8.4%	75.63%		19,615	1.7%	19.37%		1,275	9.4%	1.26%		3,790	17.3%	3.74%
1996		94,370		70,690	n/a	74.91%		19,285	n/a	20.44%		1,165	n/a	1.23%		3,230	n/a	3.42%

The region is served by the Exo La Presqu’Île and Exo Sud-Ouest bus services as well as the Vaudreuil-Hudson commuter rail line.

Highways and numbered routes that run through the municipality, including external routes that start or finish at the county border:^[25]

• List of regional county municipalities and equivalent territories in Quebec