Ardenne Castle, or the Royal Castle of Ardenne (Château Royal d'Ardenne, formerly also spelled "Hardenne") was situated in the municipality of Houyet in Belgium not far from Ciergnon Castle. The construction of the building was ordered in 1874 by King Leopold II of Belgium, to the plans of his architect Alphonse Balat. It replaced an older hunting lodge built in the 1830s by Leopold I.