London is a city in Southwestern Ontario, Canada, located along the Quebec City–Windsor Corridor. According to the 2021 Canadian census, the city had a population of 422,324. It sits at the confluence of the Thames River and North Thames River, positioning it approximately 200 kilometres from both Toronto and Detroit, and about 230 kilometres from Buffalo.
London is the county seat of Middlesex County, though it maintains political independence from the county itself. The city's strategic location along major transportation corridors has historically shaped its development as a regional centre in Southwestern Ontario.