Crug Mawr is a hill in the Black Mountains in 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 ...

in southern

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 ...

. Its summit at a height of 550 m (1,805 ft) is marked by a

trig point A triangulation station, also known as a trigonometrical point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity. The station is usually set up by a map ...

. The peak sits high above the valleys of the Grwyne Fawr and Grwyne Fechan to the north of the more well-known

Sugar Loaf A sugarloaf was the usual form in which refined sugar was produced and sold until the late 19th century, when granulated and cube sugars were introduced. A tall cone with a rounded top was the end product of a process in which dark molasses, a ...

. The views from here across the Black Mountains are wide-ranging and also extend eastwards across

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 ...

. Four ridges run off to the northwest, east, southeast and southwest, the last ending in the subsidiary summit of Blaen-yr-henbant.

Access

All of the upper slopes of the hill are designated as open country. A bridleway runs up from the minor road east of

Llanbedr Llanbedr () is a village and Community (Wales), community south of Harlech. Administratively, it lies in the Ardudwy area, formerly Meirionnydd, of the county of Gwynedd, Wales. In 2011 the community had a population of 645. History Ancient ...

and then on northwards to Mynydd Du Forest. The

Beacons Way The Beacons Way (Welsh: Ffordd y Bannau) is a waymarked long distance footpath in the Brecon Beacons National Park, Wales. It is a linear route which runs for east to west through the National Park, and passes many of the most important landmar ...

runs across the slopes of the hill between

Partrishow Partrishow, also known as Patricio, Patrishow, or by its Welsh names Merthyr Isw and Llanisw, is a small village and historic parish in the county of Powys (historically Brecknockshire), close to its border with Monmouthshire. It is in the valle ...

and Llanbedr.

Geology

In common with other hills in the Black Mountains, Crug Mawr is formed from mudstones and sandstones of the

Old Red Sandstone Old Red Sandstone, abbreviated ORS, is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the eastern seaboard of North America. It ...

laid down during the

Devonian period The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding C ...

but there is little rock exposed at the surface other than in the beds of the streams which occupy valleys such as Cwm Milaid and Cwm Beusych.British Geological Survey 1:50,000 map sheet 214 'Talgarth' & accompanying sheet explanation

References

{{Reflist Mountains and hills of Powys Black Mountains, Wales