Sunlit Marsco, Glen Sligachan, Isle of Skye

The Cuillin (Scottish Gaelic: An Cuilthionn or An Cuiltheann) is a range of rocky mountains located on the Isle of Skye in Scotland. The true Cuillin is also known as the Black Cuillin to distinguish it from the Red Cuilin (na Beanntan Dearga, known locally as Red Hills) across Glen Sligachan. The Red Cuilin hills are lower and, being less rocky, have fewer scrambles or climbs. Marsco is part of the Red Cullin or Red hills.

The highest point of the Cuillin, and of the Isle of Skye, is Sgùrr Alasdair in the Black Cuillin at 992 m (3,255 ft). The Cuillin is one of 40 National Scenic Areas in Scotland.