Great Britain, island, north-western Europe, the largest of the British Isles, and a constituent part of the United Kingdom of Great Britain and Northern Ireland. It is bordered to the south by the English Channel, which separates it from continental Europe, to the east by the North Sea, and to the west by the Irish Sea and the Atlantic Ocean. It comprises, together with numerous smaller islands, the formerly separate realms of England and Scotland, and the principality of Wales; Wales and England were legally united in 1543; the governments of England and Scotland were united by the 1707 Act of Union, creating the Kingdom of Great Britain. For further details about the physical geography, population, culture, economy, government, and history of Great Britain, see United Kingdom.