The Gàidhealtachd (Scottish Gaelic pronunciation: [ˈkɛːəl̪ˠt̪əxk] ; English: Gaeldom) usually refers to the Highlands and Islands of Scotland and especially the Scottish Gaelic-speaking culture of the area. The similar Irish language word Gaeltacht refers, however, solely to Irish-speaking areas.
The term is also used to apply to areas of Nova Scotia and Glengarry County, Ontario where the distinctive Canadian dialects of Scottish Gaelic were or are still spoken.
The Highlands (Scots: the Hielands; Scottish Gaelic: a' Ghàidhealtachd [ə ˈɣɛːəl̪ˠt̪ʰəxk], lit. 'the place of the Gaels') is a historical region of Scotland, comprising the Northernmost mountain ranges on the island of Great Britain, divided by the Great Glen between the Grampian Mountains to the southeast and the Northwest Highlands, divided from the islands of the Hebrides by the Minch. The term is also used for the area north and west of the Highland Boundary Fault, although the exact boundaries are not clearly defined, particularly to the east.
Originally home to the Caledonians/Picts, the region came to be the mainland stronghold of the Hebridean Gaels, whose Q-Celtic language succeeded that of their P-Celtic neighbours. The Scottish Gaelic name of A' Ghàidhealtachd literally means "the place of the Gaels" and traditionally, from a Gaelic-speaking point of view, includes both the Western Isles and the Highlands. Culturally, the Highlands and the Lowlands diverged from the Late Middle Ages into the modern period, when Lowland Scots language replaced Scottish Gaelic throughout most of the Lowlands.