High Quality Content by WIKIPEDIA articles! Rhondda Cynon Taf, or RCT, is a county borough in the South Wales Valleys of Wales. It consists of 3 valleys: the Rhondda Valley, Cynon Valley and Taff-Ely Valley. Results from the 2001 census showed 21.1% of its 233,700 residents were able to speak, read, write or understand the Welsh language.