The road measures 11.89 miles long and would take a car obeying speed limits 22 minutes to travel its length.
The B4558 is a B Road and is located in the Zone 4 Highways Region.
This is a true long-distance route, journeying through numerous towns like BRECON, Groesffordd, Llanfrynach, Pencelli, Talybont-on-Usk, Llandetty, Llangynidr, Glanusk, Llanwysg, The Dardy, Llangattock, and CRICKHOWELL.
The road is located entirely within Powys.