The Gàidhealtachd (Scottish Gaelic pronunciation: [ˈkɛːəl̪ˠt̪əxk] (listen); English: Gaeldom) usually refers to the Highlands and Islands of Scotland and especially the Scottish Gaelic-speaking culture of the area. The corresponding Irish word Gaeltacht refers strictly to Irish-speaking areas.
"The Gàidhealtachd" is not interchangeable with "Scottish Highlands" as it refers to the language and not to the geography. Also, many parts of the Highlands no longer have substantial Gaelic-speaking populations, and some parts of what is now thought of as the Highlands have long been Scots-speaking or English-speaking areas such as Cromarty, Grantown-on-Spey, etc. Conversely, several Gaelic-speaking communities lie outwith the Highland, Argyll and Bute and Outer Hebrides council areas, for example the Isle of Arran and parts of Perth and Kinross, not to mention Nova Scotia, North Carolina, and other areas to which there was significant migration. Gàidhealtachd also increasingly refers to any region where Scottish Gaelic is spoken as a first language by much of the population.
Until a few centuries ago, the Gàidhealtachd would have included much of modern-day Scotland north of the Firth of Forth and Galloway (up until the 18th century, and maybe later), excepting the Northern Isles, as evidenced by the prevalence of Gaelic-derived place names throughout most of Scotland and contemporary accounts. These include Dundee from the Gaelic Dùn Deagh, Inverness from Inbhir Nis, Argyll from Earra-Ghàidheal, Galloway from Gall-Ghaidhealaibh, and possibly Stirling from Sruighlea (though the etymology is uncertain; see article). Gaelic speakers from what would be considered traditionally English-speaking/non-Gaelic regions today included George Buchanan (from Stirlingshire), Robert the Bruce (from Galloway), and Margaret McMurray (from Ayrshire).
For historical reasons, including the influence of a Scots-speaking court in Edinburgh and the plantation of merchant burghs in much of the south and east, the Gàidhealtachd has been reduced massively to the present region of the Outer Hebrides, the Northwest Highlands, the Skye and Loch Alsh and Argyll and Bute, with small Gaelic populations existing in Glasgow and Edinburgh. The Highland Clearances of the 18th and 19th centuries also contributed to the decline of the language, as they reduced the population of the Scottish Highlands, which were predominantly Gaelic-speaking at the time.
It has survived as a minority language among communities descended from Scottish immigrants in parts of Nova Scotia (especially Cape Breton Island), Glengarry County in present-day Ontario, Prince Edward Island, and Newfoundland and Labrador.) The Codroy Valley on the island of Newfoundland had a Gaelic-speaking minority until the 1960s.
- Dawson, Jane (1998). "The Gaidhealtachd and the emergence of the Scottish Highlands". British Consciousness and Identity: The Making of Britain, 1533–1707. Cambridge University Press: 259–300. doi:10.1017/CBO9780511660191.011. ISBN 9780521433839.
- Brown, Ian (2006). Edinburgh History of Scottish Literature: Enlightenment, Britain and Empire (1707-1918). Edinburgh University Press. pp. 21–22. ISBN 978-0-7486-3064-6.
- Watson, Moray (2010). "Scottish Gaelic in Canada". Edinburgh Companion to the Gaelic Language. Edinburgh University Press. pp. 90–104. ISBN 978-0-7486-3710-2.
- Margaret, Bennett (5 June 1975). "Some aspects of the Scottish Gaelic traditions of the Codroy Valley, Newfoundland". research.library.mun.ca.
- The Colonisation of the Gàidheal by Iain MacKinnon