town and port, Neath Port Talbot county borough, historic county of Glamorgan (Morgannwg), Wales, on the Bristol Channel. Margam Abbey, which dominated the area during the Middle Ages, was founded in 1147 by Robert, earl of Gloucester. Modern industry began in the town in 1770 with the establishment of copper smelting. The town's growth, as an outlet for the Afan valley collieries after a dock was built in 1837, intensified when rail links were established with neighbouring mining areas (including the Rhondda valley), but the town's dominant concern in the 20th century was steelmaking. The coal trade declined drastically after 1918 and was diverted from Port Talbot completely after 1953. The gigantic steelworks and hot strip mill make Port Talbot an important producer of steel and tinplate. A deepwater harbour for ore carriers up to 100,000 tons opened in 1970. The town also has become a popular seaside resort and is the administrative centre of Neath Port Talbot county borough. Pop. (2001) 35,633.