Fleurus, municipality, Wallonia Region, south-central Belgium, located between the industrial region of Charleroi and the hills sloping toward Waterloo. Built on the site of a Gallo-Roman agricultural settlement and first mentioned in 868, it was chartered in 1115 and was the scene of several important battles.

Notable architectural remains include the Romanesque church (c. 1150–1200), of which only the tower and central nave stand; the Cistercian Soleilmont Abbey; the Naveau Windmill (1667; Napoleon’s observatory during the Waterloo Campaign); and the memorial (1936) to the three French military victories. In 1690 the French under Marshal Luxembourg defeated the Germans and Dutch in Fleurus. A later victory was that of the revolutionary army (led by Marshal Jourdan), over the Austrians in 1794. Then, in 1815, prior to Waterloo, Napoleon defeated the Prussians commanded by Field Marshal Blücher. Fleurus is a junction of several local railways; industries include coal mining and the manufacture of machinery, domestic appliances, and furniture. Pop. (2008 est.) mun., 22,267.