Lochnagar, scenic mountain of coarse red granite, Aberdeenshire, Scotland, south of the River Dee in the Grampian Mountains. The mountain ridge, popularized in the 19th century by Lord Byron’s poem “Lachin y Gair,” has 11 summits with elevations greater than 3,000 feet (900 metres); the highest is Cac Carn Beag, at 3,786 feet (1,154 metres). The name Lochnagar (“Goat Lake”) originally applied only to the small loch (lake) at the foot of the eastern ridge.