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 Wye". River Wye The River Wye () is the fifth-longest river in the UK, stretching some from its source on Plynlimon in mid Wales to the Severn estuary. For much of its length the river forms part of the border between England and Wales. The Wye Valley (lower part) is an Area of Outstanding Natural Beauty. The Wye is important for nature conservation and recreation. The meaning of the name is not clear. Possibly the earliest reference to the name is "Guoy" in Nennius' early 9th Century "Historia Brittonum" and the modern Welsh name is "Gwy". The Wye was much