Merthyr Tydfil is a town in Wales, with a population of about 63,546. It is located in the historic county of Brecknockshire, near the southern end of the Brecon Beacons National Park. The town is situated on the River Taff, and is the main town of the Merthyr Tydfil County Borough. Merthyr Tydfil is famous for its role in the Industrial Revolution, as it was one of the major centres of iron and coal production in Wales. The town also has a number of historical attractions, including the ruins of Cyfarthfa Castle and the Merthyr Tydfil Heritage Trail.