London is a city in Southwestern Ontario, Canada along the Quebec City-Windsor Corridor with a metropolitan area population of 457,720; the city proper had a population of 352,395 in the 2006 Canadian census. London is the seat of Middlesex County, at the forks of the non-navigable Thames River, halfway between Toronto and Detroit, Michigan. London and the surrounding area (roughly, the territory between Kitchener-Waterloo and Windsor) is collectively known as Southwestern Ontario. The City of London is a single-tier municipality, politically separate from Middlesex County though it remains the official county seat.