Charleroi is a city and municipality located in the province of Hainaut within the Wallonia region of Belgium. Situated in the valley of the Sambre in the southwest of the country, it lies near the border with France. It holds the distinction of being the largest city in both Hainaut and Wallonia.
As of January 1, 2008, the city had a population of 201,593. Its broader metropolitan area covers approximately 1,462 square kilometers and supported a total population of 522,522 by the same date. This makes it the fifth most populous metropolitan area in Belgium, following Brussels, Antwerp, Liège, and Ghent. Residents of the city are commonly referred to as Carolorégiens or simply Carolos.