The United Kingdom, also known as Great Britain, is officially called the United Kingdom of Great Britain and Northern Ireland. Located off of the coast of mainland Europe, its closest neighbors are France and Ireland, with Northern Ireland located in the upper half of Ireland. The United Kingdom is a constitutional monarchy, with a monarch as the head of state and a prime minister as the head of government. The current establishment of the country was finalized in 1927. It spans 243,610 square kilometers.