The River Loughor (Welsh: Afon Llwchwr) in Carmarthenshire, Wales has its source at an underground lake at the Black Mountain. It flows past settlements like Ammanford, Gwaun-cae-Gurwen, Hendy (where it becomes tidal) in Carmarthenshire and Pontarddulais. It meets the sea at the Loughor estuary near the town of Loughor where it separates the south coast of Carmarthenshire with the north coast of the Gower Peninsula.
Among its tributaries is the River Amman, which joins the Loughor near Pantyffynnon.
In the 18th Century, the river was a noted salmon and sea trout river. Fish from the river was then carried on ponies to be sold a Swansea Market. The fishing declined in the 19th Century due to increasing pollution from industrialisation.
The Loughor Estuary (aka Bury inlet or Bury estuary) is the region of the estuary downstream from Loughor, towards Carmarthen Bay. This area has extensive mudflats supporting a thriving cockle industry. On the south side of the inlet the cockle industry contributes significantly to the economy of the the village of Penclawdd.
Nearer Carmarthen Bay, the estuary is flanked by salt marshes and dune systems.