Llandeilo is a community and town in Carmarthenshire, Wales, situated at the crossing of the River Towy by the A483 on a 19th-century stone bridge. Its population is 1,731, increasing to 1,795 at the 2011 Census. It is adjacent to the westernmost point of the Brecon Beacons National Park.The town is served by Llandeilo railway station on the Heart of Wales Line.