|Location Map ( geo)|
|Distance:||0.7 miles (1.1 km)|
|Meets:||A465, B4246, A40|
|Route outline (key)|
The route starts in Llanfoist at a roundabout junction with the B4246 and with the off- and on-slips of the westbound A465: part of a larger grade-separated junction with the Heads of the Valleys Road at this location. After passing beneath the main line of the A465, the A4143 meets a link to the off- and on-slips of the eastbound A465 at a second roundabout, which also serves a Waitrose supermarket.
Almost immediately after this, our route (Merthyr Road) crosses the river by the stone-arched Usk Bridge, dating back to 1563 though much widened and strengthened over the years. So far, from Llanfoist to the northern end of the bridge, the A4143 has followed the old, pre-bypass alignment of the A465. However, beyond the bridge Merthyr Road (the old main route into Abergavenny) now swings off to the right (as a detached portion of the B4246) at a third roundabout, and the A4143 continues ahead along a new build following the former alignment of the Merthyr, Tredegar and Abergavenny Railway (closed in 1958) to terminate on the A40 some 500 metres further north.
An amended OpenStreetMap trace for this route awaits uploading to the SABRE Wiki.