Montreal open house listings The Island of Montreal is located between the Montérégie and Laval. Its southern part is circled by the St. Lawrence River, while its northern part follows Rivière des Prairies. It has a population of nearly 2 million inhabitants, which makes Montreal the most densely populated region in Quebec although its surface area is one of the smallest in the province. This highly urbanized region is teeming with attractions and services. It benefits from an extensive public transportation service, including bus, metro and commuter train networks, along with an international airport.