Hay-on-Wye the north-easternmost tip of the Brecon Beacons National Park, just north of the Black Mountains. The town is just on the Welsh side of the border with Herefordshire, England, here defined by the Dulas Brook. Where the brook joins the River Wye just north of the town, the border continues northwards along the river. The Wye was the boundary between the former counties and districts of Radnorshire and Brecknockshire. The adjacent village of Cusop lies on the English side of the Dulas Brook. The nearest city is Hereford, county town of Herefordshire, some to the east. The Royal Mail depot
River Wye Gloucestershire, and Monmouthshire. The Wye abuts a range of other SSSIs in England and Wales, including the Upper Wye Gorge and Lower Wye Gorge. It is also a Special Area of Conservation and one of the most important rivers in the UK for nature conservation. It is an important migration route and wildlife corridor, as well as a key breeding area for many nationally and internationally important species. The river supports a range of species and habitats covered by European Directives and those listed under Schedule 5 of the Wildlife and Countryside Act 1981. In Powys the river lies within