London is a city in southwestern Ontario, Canada, along the Quebec City–Windsor Corridor. The city had a population of 422,324 according to the 2021 Canadian census. London is at the confluence of the Thames River and North Thames River, approximately 200 km (120 mi) from both Toronto and Detroit; and about 230 km (140 mi) from Buffalo, New York. The city of London is politically separate from Middlesex County, though it remains the county seat.