River Lugg River Lugg The River Lugg () rises near Llangynllo, Powys. It flows through the border town of Presteigne, Wales then through Herefordshire, England, to the south of Leominster where it meets a tributary, the River Arrow. Its confluence with the River Wye is at Mordiford, downstream of Hereford and from its source. Below Leominster the river was made navigable under the "River Wye & Lugg Navigation Act 1696" for improving the River Wye, and had pound locks. Despite several attempts to improve it, including making flash locks against bridges, the river was probably never a satisfactory navigation. Commercial navigation probably
River Monnow River Monnow The River Monnow () marks the England–Wales border for much of its length. After flowing through southwest Herefordshire, England, and eastern Monmouthshire, Wales, its confluence with the River Wye is approximately south of Monmouth. The Monnow rises near Craswall on Cefn Hill just below the high Black Mountains, Wales. It flows southwards, gaining the waters of its tributaries the Escley Brook and Olchon Brook near Clodock and the waters of the River Honddu, from the Welsh side of the Black Mountains, near Pandy. The river then flows briefly eastwards, to Pontrilas, where it is joined by its largest