The United Kingdom includes a total of four constituent countries: England in the center and south (population 56,286,961, 2019); Scotland in the north (5,500,250 inhabitants, 2022), Wales in the west (3,153,000 inhabitants, 2022) and Northern Ireland in the northwest (2,050,025 inhabitants, 2019). The first three (England, Scotland and Wales) together form the island of Great Britain. Northern Ireland is the northeastern part of the island of Ireland and is the only part of the Kingdom that has a land border: with Ireland.

Great Britain (England, Scotland and Wales) and Northern Ireland jointly form the United Kingdom of Great Britain and Northern Ireland, located in the British Isles between the North Sea and the Atlantic Ocean, west of Europe. Wales was already part of England before this country became part of the United Kingdom.

The United Kingdom includes England, Scotland, Wales and Northern Ireland. For more than a hundred years the island of Ireland was entirely part of it. Although the term had previously been used to describe the voluntary joining of the countries, it was not considered the name of the empire, which was officially "Kingdom of Great Britain". There was no political unity until the 18th century. Only England and Wales achieved their unity during the Middle Ages, although full integration did not occur until Henry VIII. The Kingdom of Scotland was united with its southern neighbor, the Kingdom of England, in 1603. We had to wait for the Acts of Union of 1707, which heralded the birth of the Kingdom of Great Britain. A "United Kingdom" did not emerge until 1801, after a legal coup by William Pitt that forced the Irish Parliament to unite the Kingdom of Ireland with Great Britain..