The River Loughor (/ˈlʌxər/) (Welsh: Afon Llwchwr) in Carmarthenshire, Wales has its source at an underground lake at the Black Mountain and emerges at the surface from Llygad Llwchwr which translates from the Welsh as "eye of the Loughor". It flows past Ammanford and Hendy in Carmarthenshire and Pontarddulais in Swansea. The river divides Carmarthenshire from Swansea for much of its course and it separates Hendy from Pontarddulais at the point where the river becomes tidal. The Loughor meets the sea at its estuary near the town of Loughor where it separates the south coast of Carmarthenshire from the north coast of the Gower Peninsula. Among its tributaries is the River Amman, which joins the Loughor near Pantyffynnon.