Loch Seaforth is sea loch in the Outer Hebrides. It forms the boundary between Lewis in Ross-shire and Harris in Inverness-shire. In the middle of the loch lies Seaforth Island which forms part of both counties.
The loch opens out into the Sound of Shiant. It gives its name to an extinct branch of the Clan McKenzie, founders of the Earldom of Seaforth, and a regiment, the Seaforth Highlanders, which was created in 1881 on the amalgamation of the 72nd and 78th Highlanders, the 78th having been founded in 1778 by the Earl of Seaforth. The Seaforth Highlanders amalgamated with the Queen's Own Cameron Highlanders on 7 February 1961 to form the Queen's Own Highlanders (Seaforth and Camerons).
- Location map: 57°58’48"N, 6°43’10"W