With an area of 242,500 square kilometres (93,600 sq mi), the UK is the 78th-largest sovereign state in the world.
It is also the 21st-most populous country, with an estimated 65.5 million inhabitants in 2016.
Following the partition of Ireland and the independence of the Irish Free State in 1922, which left Northern Ireland as the only part of the island of Ireland within the United Kingdom, the name "United Kingdom of Great Britain and Northern Ireland" was adopted.
Although the United Kingdom, as a sovereign state, is a country, England, Scotland, Wales and, to a lesser degree, Northern Ireland are also regarded as countries, though they are not sovereign states.
The UK consists of four countries—England, Scotland, Wales and Northern Ireland.