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 (6 km) 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. The village is on the Heads of the Valleys Road and at the southern edge of the Brecon Beacons National Park.