Muckish is a distinctive flat-topped mountain in the Derryveagh Mountains of County Donegal, Republic of Ireland. At, it is the third-highest peak in the Derryveagh Mountains and the 163rd highest in Ireland. Muckish is also the most northern and second highest of the mountain chain called the "Seven Sisters" by locals. The Seven Sisters includes: Muckish, Crocknalaragagh, Aghla Beg, Ardloughnabrackbaddy, Aghla More, Mackoght and Errigal.OverviewHigh-grade quartz sand was mined on the flanks of the mountain, and the remains of the quarry workings can be seen on its northern side. The "Miner's Path" is a route to the summit up the northern side of the mountain. Part of this route follows the path used by the workers to reach the quarry. The sand was exported and was mainly used in the manufacture of optical glass. A less difficult route to the summit begins from the Muckish Gap on the southern side of the mountain.A large cairn, visible from sea level, can be found on the summit plateau. In 2000, a large metal cross was placed on the summit, replacing a wooden one that had been destroyed in a storm. The new cross was placed much closer to the northern end of the mountain, while the cairn is towards the south.