Argenteuil (French pronunciation: [aʁʒɑ̃tœj] ) is a regional county municipality located in the Laurentides region of Quebec, Canada. Its seat is Lachute.

In 1682, Charles-Joseph d'Ailleboust was granted by Louis de Buade de Frontenac, Governor General of New France, a domain of 186 square kilometres (72 sq mi) of land. This fiefdom was bounded by the Ottawa River to the south, a line through the center of the hamlet of Carillon in the west and Clear Lake (Lac Clair) to the north. Since Ailleboust already owned a house in Argenteuil near Paris, he called his domain Argenteuil Seigneury. In 1697, the Lord of Ailleboust and his wife Catherine Le Gardeur sold their seigneury to their son Pierre d'Ailleboust d'Argenteuil. Subsequently over the years, the fiefdom was held by Pierre-Louis Panet, and then by Major Murray.

After the conquest of New France by the British in 1759 during the Seven Years' War, the British implemented their laws, but maintained certain French seigneurial rights. In 1796, Jedediah Lane, from Jericho, Vermont, bought from Major Murray several thousand acres of land on both sides of the North River (Rivière du Nord), where Lachute is today. In 1809, Thomas Barron bought the land of the territory that would become the center of the town of Lachute. Five years later, Sir John Johnson, a Loyalist from New York who had resettled in Canada after the American Revolution, bought the rest of the Argenteuil Seigneury. He built a sawmill and gave land for churches, helping to attract new settlers to Argenteuil.

In 1854, the Parliament of the Province of Canada abolished the seigneurial system, and the County of Argenteuil was created the following year. In January 1983, the Argenteuil Regional County Municipality succeeded the County of Argenteuil.

There are 9 subdivisions within the RCM:

Historical Census Data - Argenteuil Regional County Municipality, Quebec

Year Pop. ±% 1991 27,232 —     1996 28,505 +4.7% 1996A 28,568 +0.2% 2001 28,931 +1.3%	Year Pop. ±% 2006 29,922 +3.4% 2011 32,117 +7.3% 2016 32,389 +0.8%
(A) adjusted to reflect boundary changes.

Canada Census Mother Tongue - Argenteuil Regional County Municipality, Quebec
Census		Total		French				English				French & English				Other
Year		Responses		Count	Trend	Pop %		Count	Trend	Pop %		Count	Trend	Pop %		Count	Trend	Pop %
2016		31,905		26,010	1.4%	81.5%		4,820	4.1%	15.1%		425	1.1%	1.3%		650	16.1%	2.0%
2011		31,655		25,650	9.7%	81.03%		5,025	2.0%	15.87%		420	27.3%	1.33%		560	10.4%	1.77%
2006		29,460		23,375	5.6%	79.35%		5,130	2.4%	17.41%		330	10.8%	1.12%		625	31.6%	2.12%
2001		28,230		22,130	2.8%	78.39%		5,255	10.8%	18.62%		370	42.3%	1.31%		475	3.3%	1.68%
1996		28,135		21,525	n/a	76.51%		5,890	n/a	20.93%		260	n/a	0.92%		460	n/a	1.64%

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

• Argenteuil Regional Museum (Saint-André-d'Argenteuil)
• Carillon Canal
• Caserne-de-Carillon National Historic site (Carillon Barracks)
• Lachute Airport (Lachute)

• List of regional county municipalities and equivalent territories in Quebec

• Official Web site of MRC of Argenteuil
• Official Web site of the Count of Argenteuil (History of Seigniors of Argenteuil)