|From:||St Clears (SN278164)|
|Length:||4.4 miles (7.1 km)|
|Now part of:||A4066|
|Route outline (key)|
The original route of the B4313 connected the Carmarthenshire coastal town of Laugharne to the rest of the classified road network at St Clears.
It started on the then-A40 in the centre of St Clears and headed south along the High Street out of town. After crossing the River Taf it ran close to the estuary - but straighter than the river - to Laugharne. The road went through the town before ending on an unclassified road at the point where Gosport Street heads south.
In 1935 the road was upgraded to Class I status and extended along the coast to Pendine. It was given the number A4066, which it remains.