|Length:||31.3 miles (50.4 km)|
|Meets:||A483, A488, A4113, B4357, B4356, B4362, A44|
|Route outline (key)|
The B4355 is a long rural B-road in the English/Welsh border region.
It starts in the hills in Dolfor, turning south off the A483. It climbs around several hairpins to cross a watershed and reach a height of over 1500 feet before it descends around more hairpins to reach the valley of the River Teme. It then follows the valley downstream for many miles.
In the area of Felindre the Teme starts to mark the boundary between Wales and England, although the B4355 stays firmly on the Welsh side for the time being. It continues through Lloyney and Knucklas, the villages growing bigger as the valley becomes larger.
The B4355 now crosses the Heart of Wales Railway Line and carries on to Knighton, where it reaches a T-junction. This was the original line of the A488 but that road has been rerouted so now the B4355 TOTSOs right, away from the centre of town, to reach the A488. There is then a multiplex back into town to the next T-junction, followed by a short multiplex to the right along the A4113 before the B4355 turns right to regain its number. A more obvious route through town would be to turn left at the first T-junction as this quickly merges into the A4113 but this road is narrow and unclassified.
The B4355 climbs away from Knighton out of the valley. The B4357 turns off to the right over a mile later before the road descends steeply into Norton and then crosses the River Lugg into Presteigne, where the road reaches a crossroads. The road to the right is the B4356 and the B4355 TOTSOs left and becomes the dominant number in a short multiplex.
The B4355 now passes to the south of the town centre before crossing the B4362 at a short multiplex ending at a roundabout. The English border is reached a few hundred yards afterwards; the road has been running alongside the border for over 15 miles but only crosses it now.
The Hindwell Brook is crossed before the road climbs over a ridge separating this valley from the next. The road descends into the valley of the River Arrow before ending at a roundabout on the A44 Kington bypass.
In 1922 the B4355 started on the B4362 in Presteigne and headed south to Kington, ending on the A44 in the centre of town. Its current route through Presteigne was unclassified. The road north to Knighton was the B4359 and the rest was unclassified.
In 1935 the B4355 was extended via the B4359 to Knighton and then on to Dolfor. Its route has remained more-or-less constant since, with reroutings in Knighton, Presteigne and Kington due to bypasses.