Windsor ( WIND-zer) is a city in southwestern Ontario, Canada. It is situated on the south bank of the Detroit River directly across from the U.S. city of Detroit, Michigan. Geographically located within but administratively independent of Essex County, it is the southernmost city in Canada and marks the southwestern end of the Quebec City–Windsor Corridor. The city's population was 229,660 at the 2021 census, making it the third-most populated city in Southwestern Ontario, after London and Kitc