The Black Mountains are a group of hills spread across parts of Powys and Monmouthshire in southeast Wales, and extending across the England–Wales border into Herefordshire. They are the easternmost of the four ranges of hills that comprise the Brecon Beacons National Park, and are frequently confused with the westernmost, which is known as the Black Mountain. The Black Mountains may be roughly defined as those hills contained within a triangle defined by the towns of Abergavenny in the southeast, Hay-on-Wye in the north and the village of Llangors in the west. Other gateway towns to the Black Mountains include Talgarth and Crickhowell. The range of hills is well known to walkers and ramblers for the ease of access and views from the many ridge trails, such as that on the Black Hill in Herefordshire, at the eastern edge of the massif. The range includes the highest public road in Wales at Gospel Pass, and the highest point in southern England at Black Mountain.
Waun Fach is, with a summit height of 811 metres (2,661 ft), the highest mountain in the Black Mountains in south-eastern Wales. It is one of the three Marilyns over 600 m that make up the range, the others being Black Mountain and Mynydd Troed. To the north Rhos Fawr and the Radnor Forest can be seen. It is the third highest mountain in Britain south of Snowdonia. It is situated at the head of the Grwyne Fechan valley, above and to the west of the Grwyne Fawr reservoir. It has an undistinguished rounded summit. The nearby tops on the ridge, Pen Trumau and Pen y Gadair Fawr, although lower, are very much more recognisable.
The Sugar Loaf, sometimes called Sugar Loaf, is a hill situated 2 miles (3.2 km) north-west of Abergavenny in Monmouthshire, Wales and sits within the Brecon Beacons National Park. It is the southernmost of the summit peaks of the Black Mountains, with a height of 1,955 feet (596 metres). Sugar Loaf was gifted to the National Trust by suffragette Lady Rhondda.
Twmpa or Lord Hereford's Knob is a mountain in south-east Wales, forming a part of the great northwest scarp of the Black Mountains. It lies 1.86 miles (3 km) west of the border with England, and around 4.34 miles (7 km) south of Hay-on-Wye. To the northeast lies the Gospel Pass through which runs a minor road between Hay and the Llanthony Valley. A ridge known as Darren Lwyd tapers away for about 3 kilometres (1.9 mi) to the southeast of the summit.
The Grwyne Fawr is a river in the Brecon Beacons National Park in south Wales. A section of it forms the administrative border between Powys and Monmouthshire and also of the historic counties of Brecon and Monmouth. The river and its major tributary the Grwyne Fechan flow into the River Usk at Glangrwyney.
Allt yr Esgair is a hill in the Brecon Beacons National Park in Powys, Wales. It is commonly referred to locally as simply 'The Allt'. The Welsh name signifies 'wooded slope of the ridge'. It takes the form of a northwest-southeast aligned ridge which rises to a height of 393m and which overlooks the valley of the River Usk to the west and south. To the northeast are panoramic views across Llangorse Lake to the Black Mountains There is a viewfinder on the summit erected as a monument to Eirene Lloyd White, Baroness White of Rhymney. It is a Marilyn with a prominence of 199 metres.
Y Garn Goch is a hill in the Brecon Beacons National Park in the east of Carmarthenshire, Wales. The name means the 'red cairn'. It lies near the village of Bethlehem, three miles southwest of Llangadog and four miles east of Llandeilo on the southern side of the broad Towy Valley. It is also commonly known as either Garn Goch or Carn Goch. Current owners and land managers are the Brecon Beacons National Park Authority.
Cefn Cul is a hill in the Fforest Fawr sector of the Brecon Beacons National Park in Powys, southern Wales. It is a broad north-northeast to south-southwest aligned ridge whose summit reaches a height of 562 m above sea level. The hill is bounded to the west by the upper valley of the River Tawe though which the old Trecastle road runs whilst to the east is the pass of Bwlch Bryn-rhudd over which the A4067 road runs from the Crai valley south to that of the Tawe.
Trichrug is a hill four miles east of Llandeilo and 3 miles south of Llangadog in the county of Carmarthenshire, southwest Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit at a height of 415m above sea level is marked by a trig point. It is a Marilyn with a prominence of 191 metres.
Mynydd Myddfai is a hill 4.5 miles southeast of Llandovery in the county of Carmarthenshire, southwest Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. The hill is in the form of a broad ridge aligned southwest to northeast with three or four distinct tops separated by cols. The northwest side drops steeply away towards the village of Myddfai whilst the other side is a more shallow slope down towards Glasfynydd Forest which encircles Usk Reservoir. The plateau surface of the hill rises to a height of 440m at OS grid ref SN 806297 where a trig point has been erected.
Mynydd Bach Trecastell is a hill on the border between the counties of Carmarthenshire and Powys in southwest Wales. It lies within the Black Mountain range of the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit is plateau-like and reaches a height of 412m at OS grid ref SN 827312 at Y Pigwn. The name signifies the 'little hill of castle town'.
Bryn Arw is a hill in the Black Mountains of the Brecon Beacons National Park in Monmouthshire, south Wales. It lies 4 km north of the town of Abergavenny and 1.5 miles west of the village of Llanvihangel Crucorney. Its summit at 384m above sea level is the more northerly of two tops which lie on the crest of a slightly arcuate north-south ridge which drops away to the south at first gently and then sharply. The hill is isolated from the main mass of the range by the valleys of Cwm Coed-y-cerig to the north and by Cwm Brynarw to the west. It is a Marilyn.
Gaer is the name of a hill in the Black Mountains of the Brecon Beacons National Park in Monmouthshire, south Wales. It lies at the southern end of the long ridge between the valley of the Grwyne Fawr and the Vale of Ewyas one mile to the north of Bryn Arw and 3 miles northeast of Sugarloaf. Its summit at 427m above sea level sits within an Iron Age hillfort known as Twyn y Gaer.
Mynydd Llangorse is a hill on the western edge of the Black Mountains in the Brecon Beacons National Park in Powys, south Wales. It lies two miles east of Llangors and its lake and 5 miles south of Talgarth. Its summit at 515m overtops the location 600m to the south at which a trig point is sited by 9m. The broad spur of Cefn Moel extends south towards the village of Bwlch whilst a spur to the southeast forms Pen Tir which reaches just over 450m above sea level. It is a Marilyn with a prominence of 161 metres.
The Rhiangoll is a river in the Brecon Beacons National Park in Powys, Wales. It rises on the western slopes of Waun Fach, highest point of the Black Mountains and drops steeply down to the west into the north–south valley through which the A479 runs between Talgarth and the hamlet of Tretower and through the village of Cwmdu. It is joined by various minor tributary streams on its left bank including the Ffinnant, Nant yr Ychen, Nant-y-fedw and Nantygarreg, all of which rise on the flanks of the ridge extending between the Pen Trumau spur of Waun Fach and Pen Gloch-y-pibwr. Two tributary streams flowing from Mynydd Troed and Mynydd Llangorse enter on its right bank as does Nant Ewyn east of the village of Bwlch.
Crug Mawr is a hill in the Black Mountains in the Brecon Beacons National Park in southern Powys, Wales. Its summit at a height of 550 m (1,805 ft) is marked by a trig point. The peak sits high above the valleys of the Grwyne Fawr and Grwyne Fechan to the north of the more well-known Sugar Loaf. The views from here across the Black Mountains are wide-ranging and also extend eastwards across Monmouthshire. Four ridges run off to the northwest, east, southeast and southwest, the last ending in the subsidiary summit of Blaen-yr-henbant.
Hatterrall Hill is a rounded peak in the Black Mountains which sits on the Wales-England border, partly in Monmouthshire, Wales and partly in Herefordshire, England. Its summit at 531m is the high point of a peaty plateau which falls away steeply on all sides. Broad ridges run to the north, the southeast and southwest. To the north the ridge dips to a col at around 485m elevation before rising gradually over several kilometres towards Crib y Garth / Black Hill and Hay Bluff. The ridge to the southwest ends abruptly at the sheer cliff known as the Darren below which is a considerable landslip area extending south to the hamlet of Cwmyoy with its mis-shapen church. The Welsh part of the hill falls within the Brecon Beacons National Park.
Hay Bluff is a prominent hill at the northern tip of the Black Mountains, an extensive upland massif which straddles the border between south-east Wales and England. The mountain sits at the point where the main northeast-facing escarpment of the Black Mountains meets the northwest facing escarpment, the next peak to the west being Twmpa. The flat summit of Hay Bluff which is marked by a triangulation pillar at a height of 677 metres (2,221 ft) overlooks the middle Wye Valley and the book town of Hay-on-Wye.
Buckland Hill is a low hill in the Brecon Beacons National Park in the county of Powys in Wales. Sitting transversely across the Usk valley between the river and the village of Bwlch, it provides excellent panoramic views down the valley and across to the Black Mountains. The summit at 316m above sea level is marked by an OS trig point though this is now within a dense conifer plantation and so no longer affords any outward views. Buckland Hall sits at the foot of the hill's afforested northwestern side.
Mynydd Garnclochdy is a gentle summit on the long moorland ridge which extends south from the Blorenge towards Pontypool and which defines the boundary between the modern county of Monmouthshire to the east and the county borough of Torfaen to the west though historically it was entirely within the traditional county of Monmouthshire. Its summit, at a height of 448 m (1407 ft), is marked by a small cairn. The summit and the eastern slopes of the hill fall within the Brecon Beacons National Park. A southern top of the hill, Mynydd Garn-wen achieves a height of 436m, and carries a trig point further south again at an elevation of 425m. To the north the broad moorland ridge runs via a poorly defined 425m top and a col at 404m elevation just south of a minor east–west road, into Mynydd y Garn-fawr, east of Blaenavon.
