Montérégie is an administrative region in southwest Québec. It includes the cities of Boucherville, Brossard, Granby, Longueuil, Salaberry-de-Valleyfield, Saint-Jean-sur-Richelieu, Saint-Hyacinthe, Sorel-Tracy, and Vaudreuil-Dorion.
The region has a population of 1,442,433 (2011) and a land area of , giving it a population density of 129.6 hab/km² (336/sq mi). It is the most populous region of Quebec after Montréal. The majority of the population lives near the Saint Lawrence River, on the south shore of Montreal.
Montérégie is named for the Monteregian Hills, which are in turn named for Mount Royal. Montérégie was populated by the Iroquois when the Europeans first came here in the beginning of the 17th century. Samuel de Champlain built several forts to protect the colonists against the Iroquois and against the British. Some of the battles which decided the destiny of Canada took place in Montérégie. Originally, the administrative territory of the Montérégie parishes were taken from the territory of the canonical Diocese of Saint-Jean-Longueuil.
Montérégie is known for its vineyards, orchards, spectacular panoramas, delicious products, as well as for the Monteregian Mountains, from which it draws its name. The region is both urban (second in terms of population) and rural. The Montérégie's economy is based on agriculture and the production of goods and services. Tourism also makes up a significant portion of the economy.