Llangain is a village and community in Carmarthenshire, in the south-west of Wales. Located to the west of the River Towy, and south of the town of Carmarthen, the community contains three standing stones, and two chambered tombs as well as the ruins of 15th century great house, Castell Moel. In 2001 the community's population was recorded at 574, decreasing slightly to 573 at the 2011 census.