British Isles British Isles The British Isles are an archipelago in the North Atlantic Ocean off the north-western coast of continental Europe that consists of the islands of Great Britain, Ireland, the Isle of Man and over six thousand smaller isles. They have a total area of about 315,159 km and a combined population of just under 70 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of the island of Ireland) and the United Kingdom of Great Britain and Northern Ireland. The islands of Alderney, Jersey, Guernsey and Sark, and their neighbouring smaller islands, are sometimes
Terminology of the British Isles of Celts inhabiting the islands, but this term was not used by the Greeks or Romans for the inhabitants of Britain or Ireland, nor is there any record of the inhabitants of the British Isles referring to themselves as such. Nevertheless, Roman administration later incorporated the province of Britannia into the praetorian prefecture of Gaul, in common with Hispania, which had Celtiberians. Armorica, where the Bretons would settle, was part of "Gallia Celtica", so there were tertiary relations between the Britons and Gallic Celts at least. In addition, the Parisii of Gallia Celtica are thought to have founded Aldborough in