Wikipedia
Detroit–Windsor
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.
The Detroit–Windsor area covers the southeastern Michigan counties of St. Clair, Macomb, Lapeer, Genesee, Livingston, Oakland, Washtenaw, Monroe and Wayne; as well as the Southern Ontario City of Windsor and counties of Essex, Lambton, and Kent.