The Afon Cynrig is a river in

Powys Powys ( , ) is a Principal areas of Wales, county and Preserved counties of Wales, preserved county in Wales. It borders Gwynedd, Denbighshire, and Wrexham County Borough, Wrexham to the north; the English Ceremonial counties of England, ceremo ...

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 ...

whose

headwaters The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...

rise in the central

Brecon Beacons The Brecon Beacons (; ) are a mountain range in Wales. The range includes South Wales's highest mountain, Pen y Fan (), its twin summit Corn Du (), and Craig Gwaun Taf (), which are the three highest peaks in the range. The Brecon Beacons ha ...

and flow northwards to join 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 ...

at Abercynrig just east of

Brecon Brecon (; ; ), archaically known as Brecknock, is a market town in Powys, mid Wales. In 1841, it had a population of 5,701. The population in 2001 was 7,901, increasing to 8,250 at the 2011 census. Historically it was the county town of Breck ...

. Two rivers combine to form the Cynrig just above Cantref - these being the Nant Sere and the Nant Cynwyn. They rise in two magnificent glacially carved valley heads beneath the peaks of

Pen y Fan Pen y Fan () is the highest peak in South Wales, situated in Brecon Beacons National Park (Bannau Brycheiniog). At above sea-level, it is also the highest British peak south of Cadair Idris in Snowdonia. It is the highest point (List of countie ...

and Cribyn and Cribyn and Fan y Big respectively.Ordnance Survey Explorer map OL12 'Brecon Beacons National Park: western area' The 'Gap Road', an old route from Brecon to

Merthyr Tydfil Merthyr Tydfil () is the main town in Merthyr Tydfil County Borough, Wales, administered by Merthyr Tydfil County Borough Council. It is about north of Cardiff. Often called just Merthyr, it is said to be named after Tydfil, daughter of K ...

takes advantage of Cwm Cynwyn and the col at its head to cross this range of mountains at the heart of the

Brecon Beacons National Park Brecon Beacons National Park, officially named Bannau Brycheiniog National Park (), is a National parks of the United Kingdom, national park in Wales. It is named after the Brecon Beacons (), the mountain range at its centre. The national park ...

. It has been suggested that it is of Roman origin.

References

Afon Cynrig Rivers of Powys Rivers of the Brecon Beacons National Park {{Wales-river-stub