An Bhinn Dubh

Bencollaghduff (Irish: Binn Dubh, meaning 'black mountain/peak of hags') at 696 metres (2,283 ft), is the 93rd–highest peak in Ireland on the Arderin scale, and the 115th–highest peak on the Vandeleur-Lynam scale. Bencollaghduff is situated near the centre of the core massif of the Twelve Bens mountain range in the Connemara National Park in County Galway, Ireland. It is the 3rd tallest mountain of the Twelve Bens range, after Benbaun 729 metres (2,392 ft), to which it is connected by the northern col of Maumina; and after Bencorr 711 metres (2,333 ft), to which it is connected by a high southeast rocky ridge.

Bencollaghduff's prominence of 191 metres (627 ft) qualifies it as a Marilyn, and it also ranks it as the 56th-highest mountain in Ireland on the MountainViews Online Database, 100 Highest Irish Mountains, where the minimum prominence threshold is 100 metres.