The western part of Great Britain and a country within the United Kingdom. Wales measures roughly 225 km (140 miles) from north to south and between 60 and 160 km from west to east, where it borders England. This border region, the Marches, is a stretch of pastureland much broken by hills, woods, and twisting rivers. It rises to the Cambrian Mountains, which stretch down the centre of the country. In the south‐east are the Brecon Beacons and coalfields, and in the south‐west the Pembroke Peninsula with its rocky coasts. Snowdonia is in the north‐west. There are deposits of coal and slate and water is an important Welsh resource. Coalmining and steel production were the main economic activities in Wales until the 1980s, when depletion of the coal seams led to closure of most of the mines. South Wales is now a major centre for the manufacture of electronic goods. Petrochemical industries have concentrated in South Wales around the deep‐water port of Milford Haven. Forestry and farming, especially the rearing of sheep and cattle, remain important. The population of Wales, which is Celtic in origin, resisted the Romans (who penetrated as far as Anglesey in a campaign against the Druids), and after the departure of the Romans was increased in size by British refugees from the Saxon invaders (c.400). By the 7th century Wales was isolated from the other Celtic lands of Cornwall and Scotland. Christianity was gradually spread throughout Wales by such missionaries as St Illtud and St David, but politically the land remained disunited, having many different tribes, kingdoms, and jurisdictions; Gwynedd, Deheubarth, Powys, and Dyfed emerged as the largest kingdoms, one notable ruler being Hwyel Dda (the Good), traditionally associated with an important code of laws.

From the 11th century the Normans colonized and feudalized much of Wales and Romanized the Church, but the native Welsh retained their own laws and tribal organization. There were several uprisings but as each revolt was crushed the English kings tightened their grip. Although Llywelyn ap Iorwerth (the Great) (ruled 1194–1240) recovered a measure of independence, Edward I’s invasion in 1277 ended hopes of a Welsh state: Llywelyn II was killed in 1282, and in 1301 Edward of Caernavon (Edward II) was made Prince of Wales. Thereafter Wales was divided between the Principality, royal lands, and virtually independent marcher lordships. The unsuccessful revolt of Owen Glendower in the early 15th century revived Welsh aspirations, but Henry VIII, the son of the Welsh Henry VII, united Wales with England in 1536, bringing it within the English legal and parliamentary systems. Welsh culture was eroded as the gentry and Church became Anglicized, although most of the population spoke only Welsh, given a standard form in the Bible of 1588, until the 19th century. The strong hold of the Nonconformists, especially of the Baptists and Methodists, made the formal position of the Anglican Church there the dominant question of Welsh politics in the later 19th century, leading to the disestablishment of the Church from 1920. The social unrest of rural Wales, voiced in the Rebecca riots, resulted in significant emigration. The Industrial Revolution brought prosperity to South Wales but during the Great Depression in the 1930s many people lost their jobs. Unemployment was exacerbated by the closure of most of the coalfields by the 1980s and remains a problem despite the introduction of a more diversified industry. Political, cultural, and linguistic nationalism survive, and have manifested themselves in the Plaid Cymru party, the National Eisteddfod, and Welsh‐language campaigns. A Welsh referendum in 1979 voted against partial devolution from the United Kingdom. A second referendum in 1997 reversed this decision by a small majority and a Welsh Assembly was established in 1999.