Sgùrr Alasdair is the highest peak of the Black Cuillin, and the highest peak on the Isle of Skye and in the Inner Hebrides, at . Like the rest of the range it is composed of gabbro, a rock with excellent grip for mountaineering. It is named for Alexander Nicolson, who made the first recorded ascent in 1873. Prior to this the mountain had been locally known as Sgurr Biorach.