|Location Map ( geo)|
|From:||Llantwit Major (SS965696)|
|Distance:||4.3 miles (6.9 km)|
|Meets:||B4265, B4268, A4222|
|Old route now:||A4222, B4595|
|Route outline (key)|
The B4270 connects the towns of Llantwit Major and Cowbridge in the Vale of Glamorgan.
Beginning today at a roundabout on the B4365 Llantwit and Bovington bypass, some 600 m north of its original start-point in Llantwit High Street, the road runs north for 3.7 km to Nash Corner (south of Llysworney). Here, at a junction with the B4268, it turns northeastward to complete its run to the A4222 at West Village, Cowbridge. Between Llantwit and Nash the road passes the eastern end of the former RAF Llandow, site of the 2012 National Eisteddfod of Wales.
All of the above was numbered B4267 in 1922 and only became part of the B4270 in 1935. The original route of the B4270 left Cowbridge to the north, heading along Aberthin Road. It went through Pontyclun and entered Llantrisant along Cowbridge Road, to end on the A473 in Talbot Green.
The 1935 renumberings meant that the road ran from the coast inland to Llantrisant, with a short multiplex along the A48 through Cowbridge. The road was also extended beyond Llantrisant via Beddau to return to the A473 at Tynant.
The original section of the B4270 was renumbered A4222 in the 1960s, leaving the southern extension as the only part of the B-road; the northern extension was too far away to retain this number so became the B4595 instead.