Caledonia is the Latin name given by the Romans to the land in today’s Scotland,
north of their province of Britannia, beyond the frontier of their empire. The etymology of the name is probably from a P-Celtic source. Its modern usage is as a romantic or poetic name for Scotland as a whole, comparable with Hibernia for Ireland and Cambria for Wales.
The exact location of what the Romans called Caledonia in the early stages of Britannia is uncertain, and the boundaries are unlikely to have been fixed until the building of Hadrian’s Wall. From then onwards, Caledonia stood to the north of the wall, and to the south was the Roman province of Britannia (consisting of most of what is now England and Wales).During the brief Roman military incursions into central and northern Scotland, the Scottish Lowlands were indeed absorbed into the province of Britannia, and the name was also used by the Romans, prior to their conquest of the southern and central parts of the island, to refer to the whole island of Great Britain.
The modern use of “Caledonia” in English and Scots is either as a historical description of northern Britain during the Roman era or as a romantic or poetic name for Scotland as a whole.
In music, “Caledonia” is a popular folk ballad written by Dougie MacLean in 1977 and published in 1979 on an album of the same name; it has since been covered by various other artists, including Amy Macdonald