A steep and rocky mountain situated on the boundary between Argyll & Bute and Highland Council Areas, Beinn Trilleachan rises to 839m (2752 feet) overlooking Loch Etive from the north, about 2 miles (3 km) southwest of the head of the loch. It is classified as a Corbett. Beinn Trilleachan lies to the southwest of Beinn Sgulaird and Glen Ure lies to the northwest.