Cardiff (kär´dĬf), Welsh Caerdydd, city and county (1998 est. pop. 320,900), S Wales, on the Taff River near its mouth on the Bristol Channel. Cardiff is the capital of Wales and an important port. Until the early 20th cent. it was one of the greatest coal-shipping ports in the world. Modern industries include retailing, services, engineering, oil and gasoline distribution, and food processing. Studios of the British Broadcasting Corp. are located in Cardiff, which is also the center of the Welsh-language broadcasting industry. The construction of docks by the 5th marquess of Bute in 1839 stimulated the city's growth. The port includes the docks at Penarth and Barry. There is also a canal to Merthyr Tydfil (opened 1794), with a branch to Aberdare.
Cardiff Castle, the residence of the marquess of Bute until 1947, was first built in 1090 on the site of a Roman fort. Robert, duke of Normandy, was imprisoned (1126–34) in the castle. Owen Glendower partly destroyed it in 1404. In Cathays Park the group of public buildings includes the National Museum of Wales, the law courts, and the city hall. Cardiff Univ., Cardiff Metropolitan Univ., and a campus of the Univ. of South Wales are there. The former docklands of Cardiff Bay are now the site of the new Senedd (National Assembly) building and a multipurpose cultural center. The city also has a botanic garden. Llandaff, which has a notable medieval cathedral, has been incorporated in Cardiff since 1922. The parish church of St. John dates partly from the 13th and 15th cent., and the Museum of Welsh Life, on the city's outskirts, groups buildings from throughout Wales.