Le Rœulx is a Walloon municipality located in the Belgian province of Hainaut. On January 1, 2006, Le Rœulx had a total population of 7,977. The total area is 42.80 km² which gives a population density of 186 inhabitants per km².The municipality consists of the following sub-municipalities: Le Rœulx proper, Gottignies, Mignault, Thieu, and Ville-sur-Haine.