The road measures 18.96 miles long and would take a car obeying speed limits 26 minutes to travel its length.
The B4521 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 ABERGAVENNY, Llantilio Pertholey, Llanddewi Skirrid, Bryn-y-Gwenin, Llanvetherine, Cross Ash, Skenfrith, Norton Skenfrith, Broad Oak, Three Ashes, Peterstow, and St. Owens Cross.
The road connects Gwent and Herefordshire.