The Lion's Mound is a large conical artificial hill in the municipality of Braine-l'Alleud, Walloon Brabant, Belgium. King William I of the Netherlands ordered its construction in 1820, and it was completed in 1826. It commemorates the spot on the battlefield of Waterloo where the king's elder son, Prince William of Orange, is presumed to have been wounded on 18 June 1815, as well as the Battle of Quatre Bras, which had been fought two days earlier.