The River Clydach is a short, steep and fast-flowing river in

Monmouthshire Monmouthshire ( ; ) is a Principal areas of Wales, county in the South East Wales, south east of Wales. It borders Powys to the north; the English counties of Herefordshire and Gloucestershire to the north and east; the Severn Estuary to the s ...

and the county borough of

Blaenau Gwent Blaenau Gwent (; ) is a Principal areas of Wales, county borough in the South East Wales, south-east of Wales. It borders the Local government in Wales, unitary authority areas of Monmouthshire and Torfaen to the east, Caerphilly County Borough ...

in south

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

. It lies within the Brecon Beacons National Park. It is around in length. The river rises on the southern slopes of Mynydd Llangatwg () then heads south-east through Clydach Dingle past

Brynmawr ; ; ; ) is a market town, community (Wales), community and Wards and electoral divisions of the United Kingdom, electoral ward in Blaenau Gwent, Wales. The town, sometimes cited as the highest town in Wales, is situated at above sea level at ...

. It then enters the spectacular Clydach Gorge, dropping about to Gilwern and its confluence with the

River Usk The River Usk (; ) rises on the northern slopes of the Black Mountain (''y Mynydd Du''), Wales, in the westernmost part of the Brecon Beacons National Park. Initially forming the boundary between Carmarthenshire and Powys, it flows north int ...

"Clydach" is a common name for watercourses in south Wales and is thought to derive from an old Welsh word for "swift" or possibly "stoney", both of which would apply in this case.Owen, H. W., & Morgan, R. (2007). ''Dictionary of the Place-names of Wales''. Gomer Press, Ceredigion.

References

Clydach Clydach Clydach Clydach {{Wales-river-stub