Carmarthenshire is a unitary authority in the south-west of Wales and is the largest of the thirteen historic counties of Wales. The three largest towns are Llanelli, Carmarthen and Ammanford. Carmarthen is the county town and administrative centre of Carmarthenshire, but the most populous settlement is Llanelli.
Carmarthenshire has been inhabited since prehistoric times. The town of Carmarthen was founded by the Romans, and the region was part of the Principality of Deheubarth during the High Middle Ages. It saw turbulent times during the invasion by the Normans in the 12th and 13h centuries before it was subjugated, along with other parts of Wales, by Edward I of England. There was further unrest in the early 15th century when the Welsh rebelled under Owain Glyndŵr, and more strife during the English Civil War in the 17th century.