Hay-on-Wye in Hay is a sub-office of Hereford, and therefore although in Wales has an English postal address, being part of the HR3 postcode. Hay-on-Wye is a Welsh community with a Town Council. Its boundary follows the English border/Dulas Brook from the River Wye southeastwards for just over a kilometre, turns south-west to a point just south of Oakfield house, thence north to Greenpit Farm and north westwards, enclosing the Hay Showground and meeting the National Park boundary near the B4350, Brecon Road. From this point, it follows the National Park boundary to the River Wye and the river back to
Wye Valley in the area of Symonds Yat and Slaughter Stream Cave near Berry Hill. At St Arvans, near Chepstow, the underground watercourses have carved out long cave systems, which exit at Otter Hole at the base of Piercefield cliffsthe only cave system in England or Wales which can only be reached through a tidal sump, making it a mecca for experienced cavers. Lancaut and Ban-y-Gor are Gloucestershire Wildlife Trust nature reserves. They both have SSSI status being part of the nationally important Lower Wye Gorge SSSI and within the Wye Valley AONB. The Wye Valley is important for its rich wildlife