B4300 (Black Mountain)
|Distance:||13.9 miles (22.4 km)|
|Met:||A474, B4299, A40|
|Now part of:||A4069|
|Route outline (key)|
The original route of the B4300 crossed the Black Mountain in eastern Carmarthenshire.
After reaching a summit of over 1600 feet near Foel Fawr it descended, with the descent steeper and more winding than the climb. The road reached the valley of the River Sawdde and followed that north to Llangadog, where it ended in the centre of the village on the A40.