Berg Castle (Luxembourgish: Schlass Bierg, pronounced [ˈʃlɑs ˈbiːɐ̯ɕ]; French: Château de Berg; German: Schloss Berg) is the principal residence of the Grand Duke of Luxembourg. It is situated in the town of Colmar-Berg, in central Luxembourg, near the confluence of the Alzette and the Attert, two of Luxembourg's most important rivers.