Rhondda ˈrɒnðə, or the Rhondda Valley (Cwm Rhondda kʊm ˈr̥ɔnða), is a former coalmining area in South Wales, historically in the county of Glamorgan. It takes its name from the River Rhondda, and embraces two valleys – the larger Rhondda Fawr valley (mawr large) and the smaller Rhondda Fach valley (bach small) – so that the singular "Rhondda Valley" and the plural are both commonly used. The area forms part of the South Wales Valleys. From 1897 until 1996 there was a local government district of Rhondda. The former district at its abolition comprised sixteen communities. Since 1996 these sixteen communities of the Rhondda have been part of Rhondda Cynon Taf County Borough. The area of the former district is still used as the Rhondda Senedd constituency and Westminster constituency, having an estimated population in 2020 of 69,506. It is most noted for its historical coalmining industry, which peaked between 1840 and 1925. The valleys produced a strong Nonconformist movement manifest in the Baptist chapels that moulded Rhondda values in the 19th and early 20th centuries. It is also known for its male voice choirs and in sport and politics.
In the early Middle Ages, Glynrhondda was a commote of the cantref of Penychen in the kingdom of Morgannwg, a sparsely populated agricultural area. The spelling of the commote varied widely, as the Cardiff Records show:
Many sources state the meaning of Rhondda as "noisy", though this is a simplified translation without research. Sir Ifor Williams, in his work Enwau Lleoedd, suggests that the first syllable rhawdd is a form of the Welsh adrawdd or adrodd, as in "recite, relate, recount", similar to the Old Irish rád; 'speech'. The suggestion is that the river is speaking aloud, a comparison to the English expression "a babbling brook".
With the increase in population from the mid-19th century the area was officially recognised as the Ystradyfodwg Local Government District in 1877, but was renamed in 1897 as the Rhondda Urban District after the River Rhondda.