The Detroit–Windsor region is an international transborder agglomeration comprising the American city of Detroit, Michigan, the Canadian city of Windsor, Ontario and the Detroit River between them. The Detroit–Windsor area acts as a critical commercial link straddling the Canada–United States border and has a total population of about 5,700,000. It is North America's largest cross-border conurbation. Quebec City–Windsor Corridor contains 18 million people, with 51% of the Canadian population and three out of the four largest metropolitan areas, according to the 2001 Census.