Wales (Welsh: Cymru [ˈkəm.rɨ] (listen)) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in 2021 of 3,107,500 and has a total area of 20,779 km² (8,023 sq mi). Wales has over 1,680 miles (2,700 km) of coastline and is largely mountainous with its higher peaks in the north and central areas, including Snowdon (Yr Wyddfa), its highest summit. The country lies within the north temperate zone and has a changeable, maritime climate. The capital and largest city is Cardiff.

Welsh national identity emerged among the Celtic Britons after the Roman withdrawal from Britain in the 5th century, and Wales was formed as a kingdom under Gruffydd ap Llywelyn in 1055. Wales is regarded as one of the Celtic nations. After over 200 years of war, the conquest of Wales by King Edward I of England was completed by 1283, though Owain Glyndŵr led the Welsh Revolt against English rule in the early 15th century, and briefly re-established an independent Welsh state with its own national parliament (Welsh: senedd). In the 16th century the whole of Wales was annexed by England and incorporated within the English legal system under the Laws in Wales Acts 1535 and 1542. Distinctive Welsh politics developed in the 19th century. Welsh Liberalism, exemplified in the early 20th century by David Lloyd George, was displaced by the growth of socialism and the Labour Party. Welsh national feeling grew over the century; a nationalist party, Plaid Cymru was formed in 1925, and the Welsh Language Society in 1962. A governing system of Welsh devolution is employed in Wales, of which the most major step was the formation of the Senedd (Welsh Parliament, formerly the National Assembly for Wales) in 1998, responsible for a range of devolved policy matters.

At the dawn of the Industrial Revolution, development of the mining and metallurgical industries transformed the country from an agricultural society into an industrial one; the South Wales Coalfield's exploitation caused a rapid expansion of Wales' population. Two-thirds of the population live in South Wales, including Cardiff, Swansea, Newport and the nearby valleys. The eastern region of North Wales has about a sixth of the overall population, with Wrexham being the largest northern city. The remaining parts of Wales are sparsely populated. Now that the country's traditional extractive and heavy industries have gone or are in decline, the economy is based on the public sector, light and service industries, and tourism. Agriculture in Wales is largely livestock based, making Wales a net exporter of animal produce, contributing towards national agricultural self-sufficiency.

The country has a distinct national and cultural identity and from the late 19th century onwards Wales acquired its popular image as the "land of song", in part due to the eisteddfod tradition and rousing choir singing. Both Welsh and English are official languages. A majority of the population in most areas speaks English whilst a majority of the population in parts of the north and west speak Welsh, with a total of 538,300 Welsh speakers across the whole country.