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
Upper Wye Gorge fritillary and the white admiral. Upper Wye Gorge Upper Wye Gorge is a Site of Special Scientific Interest (SSSI), noted for its biological and geological characteristics, around Symonds Yat in the Upper Wye Valley on the Wales–England border. The site is listed in the 'Forest of Dean Local Plan Review' as a Key Wildlife Site (KWS). The SSSI, of which are in England and are in Wales, notified in 1969, is located north east of the town of Monmouth. It lies within the civil parishes of Goodrich and Whitchurch in Herefordshire, English Bicknor in Gloucestershire and within the community of