A466 road about long and runs through the counties of Herefordshire and Gloucestershire in England, and Monmouthshire in Wales. It runs south from Kingsthorne, on the A49 south east of Hereford to Monmouth, crossing the A40. After crossing the River Wye at the Wye Bridge, Monmouth and Bigsweir Bridge near Llandogo, it follows a picturesque route south down the Wye valley through Tintern and Chepstow to the M48 motorway at junction 2. The road crosses the border between England and Wales at three places along its length: at Buckholt, Redbrook, and Bigsweir. It runs through an Area of Outstanding Natural Beauty, and
England–Wales border the border between Wales and England, a border which has survived until today. It did not follow the old line of Offa's Dyke nor the eastern boundary of the Welsh dioceses; it excluded districts such as Oswestry and Ewias, where the Welsh language would continue to be spoken for centuries, districts which it would not be wholly fanciful to consider as "Cambria irredenta". Yet, as the purpose of the statute was to incorporate Wales into England, the location of the Welsh border was irrelevant to the purposes of its framers. An 1844 Act of Parliament later abolished several enclaves. One