Knock Castle is a ruined tower house dating from about 1600 and located a mile west from the town of Ballater, Aberdeenshire, Scotland (Scottish Gaelic: Bealadair, Siorrachd Obar Dheathain, Alba). Knock Castle is now without a roof, rectangular and four stories high. It about 27 feet by 22 feet and the falls are some 4 feet thick. A short distance to the west is a motte, with the possible foundations of an earlier 12th-century timber fortress, known as the Old Castle Knock.