The road measures 10.55 miles long and would take a car obeying speed limits 19 minutes to travel its length.
The B4312 is a B Road and is located in the Zone 4 Highways Region.
This is a true long-distance route, journeying through numerous towns like Llansteffan, Llangain, CARMARTHEN, Llanllwch, and Johnstown.
The road is located entirely within Dyfed.