Aberdare (Welsh: Aberdâr) is an industrial town in the county borough of Rhondda Cynon Taff in the traditional county of Glamorgan, in south Wales, situated (as the name implies) at the confluence of the Dar and Cynon rivers. The population at the (1991) census was 31,619. It is 4 miles S.W. of Merthyr Tydfil and 24 miles N.W. of Cardiff. From being, at the beginning of the 19th century, a mere village in an agricultural district, the place grew rapidly in population owing to the abundance of its coal and iron ore, and the population of the whole parish (which was only 1486 in 1801) increased tenfold during the first half of the century. It has since declined, owing to the loss of most of the heavy industry.