The Afon Llwchwr, also known as the River Loughor, is a significant river in South Wales that forms the border between Carmarthenshire and Swansea. It originates from a series of limestone caves within the Black Mountain in the western Brecon Beacons, a source known as Llygad Llwchwr (eye of the Loughor). From its headwaters, the river flows southward through Ammanford, Garnswllt, and Pontarddulais, collecting tributaries like the Amman and Morlais. At Pontarddulais, the river becomes tidal and enters its estuary, the Burry Inlet, approximately 20 miles from its source. The river is historically noted for its salmon and sea trout (sewin) fishing, though it also offers diverse angling opportunities for other species.