CARMARTHEN (Caerfyrddin), a municipal borough, contributory parliamentary borough (united with Llanelly since 1832), and county town of Carmarthenshire, and a county of itself, finely situated on the right bank of the Towy, which is here tidal and navigable for small craft.
The place probably owes its Celtic name of Llan-ym-ddyffri (the church amid the waters) to the proximity of Llandingat church to the streams of the Towy, Bran and Gwydderig.
On account of its commanding position at the head of the fertile vale of Towy, Llandovery was a strategic site of some importance in the middle ages.
The Wye is the chief river, and forms the boundary between the county and Radnorshire on the north and north-east, from Rhayader to Hay, a distance of upwards of 20 m.; its tributary, the Elan, till it receives the Claerwen, and then the latter river, continue the boundary between the two counties on the north, while the Towy separates the county from Cardigan on the north-west.
The Towy (68 m.) flows through Carmarthenshire, entering Carmarthen Bay at Llanstephan; the Teifi (50 m.) rises near Tregaron and falls into Cardigan Bay below the town of Cardigan.