The Irish Sea lies between Great Britain and Ireland.
A treaty between England and Scotland resulted in 1707 in a unified Kingdom of Great Britain, which merged in 1801 with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland.
In 1922, five-sixths of Ireland seceded from the country, leaving the present formulation of the United Kingdom of Great Britain and Northern Ireland.
These are the remnants of the British Empire which, at its height in the 1920s, encompassed almost a quarter of the world's land mass and was the largest empire in history.
British influence can be observed in the language, culture, and legal systems of many of its former colonies.
It is also the 21st-most populous country, with an estimated 65.1 million inhabitants.The monarch—since 6 February 1952—is Queen Elizabeth II.