The River Taff is a river in Wales. It rises as two rivers in the Brecon Beacons; the Taf Fechan and the Taf Fawr before becoming one just north of Merthyr Tydfil. Its confluence with the River Severn estuary is in Cardiff.

Cardiff is the capital and largest city of Wales. Cardiff had a population of 362,310 in 2021 and forms a principal area officially known as the City and County of Cardiff. The city is the eleventh largest in the United Kingdom. Located in the southeast 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.