Map - Cardiff

Cardiff (Caerdydd ) is the capital and largest city of Wales. Cardiff had a population of 481,000 in 2021, forms a principal area officially known as the City and County of Cardiff (Dinas a Sir Caerdydd), and the city is the eleventh-largest in the United Kingdom. Located in the south-east of Wales and in the Cardiff Capital Region, Cardiff is the county town of the historic county of Glamorgan and in 1974–1996 of South Glamorgan. It belongs to the Eurocities network of the largest European cities. A small town until the early 19th century, its prominence as a port for coal when mining began in the region helped its expansion. In 1905, it was ranked as a city and in 1955 proclaimed capital of Wales. Cardiff Built-up Area covers a larger area outside the county boundary, including the towns of Dinas Powys and Penarth.

Cardiff is the main commercial centre of Wales as well as the base for the Senedd. At the 2021 census, the unitary authority area population was put at 362,400. The population of the wider urban area in 2011 was 479,000. In 2011, it ranked sixth in the world in a National Geographic magazine list of alternative tourist destinations. It is the most popular destination in Wales with 21.3 million visitors in 2017.

Cardiff is a major centre for television and film production (such as Doctor Who, Torchwood and Sherlock) and is the Welsh base for the main national broadcasters.

Cardiff Bay contains the Senedd building (home to the Senedd, the Welsh Parliament) and the Wales Millennium Centre arts complex. Work continues at Cardiff Bay and in the centre, on projects such as Cardiff International Sports Village, BBC drama village, and a new business district.

Caerdydd (the Welsh name of the city) derives from the Middle Welsh Caerdyf. The change from -dyf to -dydd shows the colloquial alteration of Welsh f and dd, and was perhaps also driven by folk etymology. This sound change had probably first occurred in the Middle Ages; both forms were current in the Tudor period. Caerdyf has its origins in post-Roman Brythonic words meaning "the fort of the Taff". The fort probably refers to that established by the Romans. Caer is Welsh for fort and -dyf is in effect a form of Taf (Taff), the river which flows by Cardiff Castle, with the t showing consonant mutation to d and the vowel showing affection as a result of a (lost) genitive case ending.

The anglicised Cardiff is derived from Caerdyf, with the Welsh f borrowed as ff, as also happens in Taff (from Welsh Taf) and Llandaff (from Welsh Llandaf).

The antiquarian William Camden (1551–1623) suggested that the name Cardiff may derive from *Caer-Didi ("the Fort of Didius"), a name supposedly given in honour of Aulus Didius Gallus, governor of a nearby province at the time when the Roman fort was established. Although some sources repeat this theory, it has been rejected on linguistic grounds by modern scholars such as Professor Gwynedd Pierce.