Both Ireland and the United Kingdom joined the European Union (then the European Communities) in 1973. However, the three Crown dependencies remained outside of the EU. In June 2016, the UK held a referendum in which a majority voted to leave the EU.

The United Kingdom of Great Britain and Ireland was the union of the Kingdom of Great Britain and the Kingdom of Ireland into one sovereign state, established by the Acts of Union in 1801. [4] It continued in this form for over a century.

The island of Ireland comprises the Republic of Ireland, which is a sovereign country, and Northern Ireland, which is part of the United Kingdom. The Republic of Ireland endured a hard-fought birth.

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, [m] is a country in Northwestern Europe, off the coast of the continental mainland.It comprises England, Scotland, Wales, and Northern Ireland. [n] The UK includes the island of Great Britain, the north-eastern part of the island of Ireland, and most of the smaller islands within the ...

So, in summary: The U.K. is a sovereign state that includes England, Wales, Scotland, and Northern Ireland; Great Britain (or simply Britain) is an island; Ireland is an island situated next to Great Britain, which is divided in two countries: The Republic of Ireland, and Northern Ireland.

Ireland was the 6th largest trading partner for the UK in 2023, while over one third of Irish exports go to the UK. The UK remains the largest single destination for Irish food, drink and horticulture exports, reflecting the important two-way relationship between Ireland and our nearest neighbour.

Information for UK nationals moving to or living in Ireland, including guidance on residency, healthcare and driving.

Act of Union, (Jan. 1, 1801), legislative agreement uniting Great Britain (England and Scotland) and Ireland under the name of the United Kingdom of Great Britain and Ireland.

The Republic of Ireland – United Kingdom border is the border that separates the constituent British nation of Northern Ireland from the rest of Ireland. It is also known as the Irish Border or simply as the border.

The current British state, the United Kingdom of Great Britain and Northern Ireland, is universally accepted to be a direct continuation of the United Kingdom of Great Britain and Ireland, and should not be imagined to be a break from it or a new state formed after it.