cynonvalley.com £xxx The Cynon Valley (Welsh: Cwm Cynon), is a famous former coal mining valley within the South Wales Valleys of Wales. The Cynon Valley lies between the other mining Valley of Rhondda and the iron industrial Valley of the Merthyr Valley. Its main towns are Aberdare (Welsh: Aberdâr) located North of the Valley and Mountain Ash (Welsh: Aberpennar) located in the South of the Valley. . According to the 2001 Census, the Cynon Valley has a population of 63,512. In 2001 12.1% of the inhabitants were recorded as Welsh speakers. In common with the other South Wales Valleys, the Cynon Valley had a high number of Welsh speakers until the early 20th century.