The 1,150-kilometre Quebec City-Windsor Corridor is the most densely-populated and heavily-industrialised region of Canada. With over 16 million people, it contains half of the Canadian population, and three of the four largest cities in the country. Many urban areas adjacent to the corridor may be considered part of the region, having strong ties to it, such as Sherbrooke, Quebec, Buffalo, New York, and Detroit, Michigan. If these regions are included, the population could be said to be over 25 million. In its relative importance to the country's economic and political infrastructure, it has many similarities to the area along the Northeast Corridor in the United States.
The name is derived from the names of the cities at each end and was first popularized by VIA Rail, which runs frequent passenger rail service along the corridor. Much like the Northeast Corridor in the United States, the Quebec City-Windsor Corridor name has been expanded to refer to the geography and demography of the region which the corridor traverses.