Dùn Dubh is a hillfort, located on the Inner Hebridean island of Coll. The fort is one of three associated with a local tradition which states that they were once the fortresses of Norsemen before being defeated by a Maclean chieftain. The early 20th century antiquary Erskine Beveridge considered it as one of the four most interesting fortifications, on Coll. The site is located at grid reference NM18365942.

Coll is an island located west of the Isle of Mull in the Inner Hebrides of Scotland. Coll is known for its sandy beaches, which rise to form large sand dunes, for its corncrakes, and for Breacachadh Castle. It is in the council area of Argyll and Bute.