Loch Shiel (Scottish Gaelic: Loch Seile) is a freshwater loch situated 20 kilometres (12 mi) west of Fort William in the Highland council area of Scotland.
At 28 kilometres (17+1⁄2 mi) long it is the 4th longest loch in Scotland, and is the longest to have retained a natural outflow without any regulation of its water level, being 120 m (393 ft) deep.
Its nature changes considerably along its length, being deep and enclosed by mountains in the north east and shallow surrounded by bog and rough pasture in the south west, from which end the 4 km long river Shiel drains to the sea in Loch Moidart near Castle Tioram.
