The River Lugg (Welsh: Afon Llugwy) rises near Llangynllo in Radnorshire, Wales. It flows through the border town of Presteigne and then through Herefordshire, England, where it meets its main tributary, the River Arrow, to the south of Leominster. It flows into the River Wye downstream of Hereford at Mordiford, around 63 miles (101 km) from its source. Its name comes from a Welsh root, and means "bright stream".