United Kingdom

Official name

United Kingdom of Great Britain and Northern Ireland (as of 2026-09-05)^[1]

Constituent countries

England, Scotland, Wales, Northern Ireland (as of 2026-09-05)^[1]

Capital

London (as of 2026-09-05)^[1]

Total area

94,354 sq mi (244,376 km²) (as of 2026-09-05)^[1]

UK population (mid-year estimate)

69,487,000 (as of 2025)^[3]

Great Britain population (mid-year estimate)

67,353,600 (as of 2024)^[3]

England population (mid-year estimate)

58,620,100 (as of 2024)^[3]

Scotland population (mid-year estimate)

5,546,900 (as of 2024)^[3]

Wales population (mid-year estimate)

3,186,600 (as of 2024)^[3]

Northern Ireland population (mid-year estimate)

1,927,900 (as of 2024)^[3]

England, Scotland, Wales and Northern Ireland make up a sovereign state, the United Kingdom of Great Britain and Northern Ireland.^[1] It is often referred to as the UK or Britain.^[1]

Geography and terminology

Located off the coast of the continental mainland in northwestern Europe, the UK covers a total area of 94,354 square miles (244,376 km²).^[1] It shares a land border with the Republic of Ireland.^[1]

The bodies of water bordering the UK are the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea.^[1]

0:00 The UK Is a Country Made of Countries CGP Grey's video explains the relationship between the UK, Great Britain, England and the British Isles.

Population

According to Office for National Statistics, the Office for National Statistics estimated the UK population at 69,487,000 in the 2025 mid-year estimate, published on 27 November 2025.^[3]

According to Office for National Statistics, in the 2024 mid-year estimates, Great Britain's population was 67,353,600, England's was 58,620,100, Scotland's was 5,546,900, Wales's was 3,186,600 and Northern Ireland's was 1,927,900.^[3]

According to Wikipedia contributors, Wikipedia gives a figure of over 69 million for 2024; the ONS publishes a 2024 mid-year figure of 67,353,600 for Great Britain alone.^[1][3]

Capitals and cities

London is the capital and largest city of England and of the United Kingdom.^[1] Edinburgh, Cardiff and Belfast serve as the respective national capitals of Scotland, Wales and Northern Ireland.^[1]

Constitutional status and devolution

With devolved powers from Westminster, Scotland, Wales and Northern Ireland each operate their own governments and parliaments or assemblies, handling matters such as health, education, transport, justice and the environment in their respective regions.^[1]

History

The Roman conquest of Britain began in AD 43.^[1] Roman forces withdrew from the island between AD 383 and 410.^[1]

Anglo-Saxon settlement began around AD 450, and Norman forces conquered England in 1066.^[1]

Under the Treaty of Union in 1707, England and Scotland were merged to form the Kingdom of Great Britain.^[1]

Through the Acts of Union 1800, the Kingdom of Ireland was joined with Great Britain to form the United Kingdom of Great Britain and Ireland in 1801.^[1] After most of Ireland seceded in 1922 as the Irish Free State, the Royal and Parliamentary Titles Act 1927 established the present form of the United Kingdom of Great Britain and Northern Ireland.^[1]

According to Wikipedia contributors, during the Pax Britannica, from 1815 to 1914, Britain stood as the world's leading power, and the British Empire reached the height of its territorial extent in the 1920s, when it encompassed approximately a quarter of the world's land area and population.^[1]

Economy and international role

Among the world's largest economies by nominal GDP, the UK is a developed country.^[1] It ranks as one of the world's biggest exporters and importers of goods and services.^[1]

The UK is a recognised nuclear weapons state and maintains one of the higher defence budgets in Europe.^[1]

The UK holds membership of numerous international organisations.^[1]

Sovereignty beyond the UK

Although not part of the United Kingdom itself, the Crown Dependencies and the British Overseas Territories are still under UK sovereignty.^[1]

Geography Now: United Kingdom

0:00 Introduction Geography Now opens its episode on the United Kingdom with an introductory overview.

1:30 The UK Today Geography Now discusses contemporary aspects of life in the United Kingdom.

2:44 The Map Geography Now walks through the geography of the United Kingdom on a map.

5:36 Administrative Divisions Geography Now describes the administrative structure of the United Kingdom.

8:23 History Geography Now surveys the history of the United Kingdom.

15:07 Geography Geography Now describes the physical geography of the United Kingdom.

Timeline

1. 43 Roman conquest of Britain begins.^[1]
2. 383 According to Wikipedia contributors, Roman forces depart Britain.^[1]
3. 450 According to Wikipedia contributors, Anglo-Saxon settlement begins in Britain.^[1]
4. 1066 Norman forces conquer England.^[1]
5. 1707 England and Scotland unite as the Kingdom of Great Britain.^[1]
6. 1801 United Kingdom of Great Britain and Ireland created by the Acts of Union 1800.^[1]
7. 1922 Most of Ireland secedes as the Irish Free State.^[1]
8. 1927 Royal and Parliamentary Titles Act 1927 establishes the present United Kingdom of Great Britain and Northern Ireland.^[1]