Constitutional status of Cornwall in the context of Constituent country of the UK

Since 1922, the United Kingdom has been made up of four countries: England, Scotland, Wales (which collectively make up Great Britain) and Northern Ireland (variously described as a country, province, jurisdiction or region). The UK prime minister's website has used the phrase "countries within a country" to describe the United Kingdom.

Although the United Kingdom is a unitary sovereign state, it contains three distinct legal jurisdictions in Scotland, England and Wales, and Northern Ireland, each retaining its own legal system even after joining the UK. Since 1998, Northern Ireland, Scotland, and Wales have also gained significant autonomy through the process of devolution. The UK Parliament and UK Government deal with all reserved matters for Northern Ireland, Scotland, and Wales, but not in general matters that have been devolved to the Northern Ireland Assembly, Scottish Parliament, and Senedd. Additionally, devolution in Northern Ireland is conditional on co-operation between the Northern Ireland Executive and the Government of Ireland (see North/South Ministerial Council) and the British Government consults with the Government of Ireland to reach agreement on some non-devolved matters for Northern Ireland (see British–Irish Intergovernmental Conference). England, comprising the majority of the population and area of the United Kingdom, does not have its own devolved government, and remains fully the responsibility of the United Kingdom Parliament centralised in London. In July 2025, the council of the English county of Cornwall backed a motion calling for Cornwall to be regarded as the UK's fifth nation.

Cornwall (/ˈkɔːrnwəl/; Cornish: Kernow [ˈkɛrnɔʊ] or [ˈkɛrnɔ]) is a ceremonial county in South West England. It is one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, Devon to the east, and the English Channel to the south. The largest urban area is the Redruth and Camborne conurbation.

The county is predominantly rural, with an area of 1,375 square miles (3,562 km) and an estimated population of 585,655 in 2024. The county's major settlements include the city of Truro and St Austell in the centre, Redruth and Cambourne adjacent to each other in the south, and Penzance and Falmouth on the southern coast. For local government purposes most of Cornwall is a unitary authority area, with the Isles of Scilly governed by a unique local authority. The Cornish nationalist movement disputes the constitutional status of Cornwall and seeks greater autonomy within the United Kingdom.

Cornish nationalism is a cultural, political and social movement that seeks the recognition of Cornwall – the south-westernmost part of the island of Great Britain – as a nation distinct from England.

Cornish nationalism is usually based on three general arguments: