Cefneithin is a village in Carmarthenshire, Wales.
It is situated within the SA14 postcode district, which is within the Llanelli post town.
The full list of postcode districts within the Llanelli post town is as follows:
The Llanelli post town is within the Swansea postcode area.
Administrative Ward: Gorslas
Administrative District: Carmarthenshire
Country: Wales
UK Parliament: Carmarthen East and Dinefwr