A small burgh of Lochaber district, Highland region, Scotland. Fort William is sited at the foot of Ben Nevis, Britain's highest mountain, and at the edge of Loch Linnhe. The original fort was built in 1654, was later ruined and rebuilt in 1690, being named for the King William III. The fort was dismantled in the 19th century to make room for the new railway. Water is conveyed by a 24 kilometre tunnel beneath Ben Nevis into Fort William to provide power for an aluminium works. Fort William was also the first town in Britain to light its streets entirely by hydroelectricity. Pop. (1981) 11,061.