Merthyr Tydfil (pop. 58,839) is a town on the River Taff in South Wales. It is also a unitary authority (local government area). Merthyr Tydfil lies close to the Brecon Beacons National Park.
The town has a number of light industries, including engineering and the production of electrical equipment. As industries developed in the area in the 1800’s and early 1900’s, Merthyr Tydfil became the most important industrial center in Wales. But its importance declined when new ironworks were built on sites nearer to the coast.