|To:||Builth Wells (SO041509)|
|Distance:||16.4 miles (26.4 km)|
|Meets:||B4601, B4519, A483|
|Route outline (key)|
The B4520 is a hilly B-road in Brecknockshire. It was originally unclassified but gained its number in the mid-1930s.
The road starts at traffic lights on the B4601 in Brecon town centre and heads north along The Struet, which was the original western end of the A483. We take the next turn left and cross the River Honddu before skirting the cathedral grounds. After running through the suburb of Pendre we enter open country and skirt Pen-y-crug, continuing north along the valley of the River Honddu.
The river valley is narrow and so the road usually remains halfway up the right bank. We pass through small villages such as Llandefaelog Fach and presently cross the river at Lower Chapel. The river is followed as far as Upper Chapel, after which it bears off left and the B4520 continues northwards. After a short climb the B4519 bears off left, after which we climb steeply onto the moors. A cattle grid is crossed then the road levels out as it winds past the sheep.
We pass the eastern end of the Sennybridge Training Area, which may be marked by a red flag, then cross a valley. After another cattle grid the road descends, sometimes steeply, and we enter a narrow valley. The central line briefly disappears until we get enough space for it to come back. Presently we pass through Llandewi'r Cwm and then zigzag over the Afon Duhonw. There's a brief - and relatively flat - journey northwards and we enter Builth Wells along Brecon Road. In the centre of town there's a sharp left-hand bend into Market Street then we end shortly afterwards on the A483 High Street in the town's one-way system; B4520 traffic is forced to turn left.