Pirnmill (Scottish Gaelic: Muileann nam Piùirneachan) is a small village on the north-west coast of the island of Arran, Scotland.

Located within the parish of Kilmory,[1] Pirnmill is flanked by several clachans, including Whitefarland to the south, Thunderguy to the north, and the original settlement of Penrioch (Scottish Gaelic: Peighinn Riabhach) above the village.

[2] The mill was built by J&P Clarks of Paisley and powered by a 40ft water wheel that was turned a flow from a dam that was filled by the fast-flowing Allt Gobhlatch river.

[2] Early inhabitants of Pirnmill made a living through seasonal herring fishing or crofting, but later the village became a tourist destination, with many Clyde steamers plying between Glasgow and Campbeltown.

The Dougarie Estate carried out flow measurement in 2008 and 2009 on four streams, and in 2012 secured planning permission for a scheme utilising the waters of the Allt Gobhlach.

The plans were generally well-received by the villagers, and the power station, which generates 500 kW and feeds it into the National Grid, was commissioned in June 2013.

[6] Two miles (three kilometres) north of the village, halfway between Pirnmill and Catacol, there is an ancient burial ground close to the shore at Rhubha Airigh Bheirg.