South Barrule is a prominent hill in the south of the Isle of Man, rising to 1,585 feet. Its name derives from the Norse Varda-fjall, Beacon fell, indicating its use as a beacon station in the Norse signal system. The summit is crowned by a large Iron Age hillfort, one of the most significant prehistoric monuments on the Island.

It is a watershed as well as a beacon. The Water of Castletown springs from South Barrule, and the older topographers list part of the hill among the mountains of the parish of Patrick, with Dalby, Slieau Whallian, Cronk ny Slieau and part of Archallagan.

It has its own piece of folklore. When a man remembered as Dollin the Blackguard was helping himself by night to a fat wether on South Barrule, a voice out of the darkness advised him in Manx to take two sheep, and promised not to tell the Coroner.