Montérégie (French pronunciation: [mɔ̃teʁeʒi]) is an administrative region in the southwest part of Quebec. It includes the cities of Boucherville, Brossard, Châteauguay, Longueuil, Saint-Hyacinthe, Saint-Jean-sur-Richelieu, Salaberry-de-Valleyfield and Vaudreuil-Dorion.
The region had a population of 1,507,070 as of the 2016 census and a land area of 11,132.34 square kilometres (4,298.22 sq mi), giving it a population density of 135.4 inhabitants per square kilometre (351 inhabitants/sq mi). With approximately 18.5% of the province's population, it is the second most populous region of Quebec after Montreal. The majority of the population lives near the Saint Lawrence River, on the south shore of Montreal.