Hirwaun is a village and community at the north end of the Cynon Valley in the County Borough of Rhondda Cynon Taf, South Wales. It is 4 miles NW of the town of Aberdare, and comes under the Aberdare post town. At the 2001 census, Hirwaun had a population of 4,851. increasing at the 2011 census to 4,990.