Loch Arkaig is a body of freshwater in Lochaber, Scotland, to the west of the Great Glen. It is approximately 12 mi in length and lies 140 ft above sea level, and the maximum depth is around 300 ft. The loch is among the last remaining fragments of the Caledonian pinewood, which is native to the UK.

The main tributaries are the Dessarry and the Pean, which flow through the glens of