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.
Blorenge, also called The Blorenge, is a prominent hill overlooking the valley of the River Usk near Abergavenny, Monmouthshire, southeast Wales. It is situated in the southeastern corner of the Brecon Beacons National Park. The summit plateau reaches a height of 561 metres (1,841 ft).
Coity Mountain is a flat-topped mountain in the South Wales Valleys, between Blaenavon and Abertillery. The highest points of both Torfaen and Blaenau Gwent unitary authorities are at the summit of Coity Mountain. The summit is also known as Twyn Ffynhonnau Goerion. Some 2 km (1 mi) to the southeast lies a major subsidiary top of the hill, Mynydd Varteg Fawr (549m) at the southeastern end of whose broad ridge is a trig point at 544m. A few hundred metres to the southeast of this summit is a memorial known as the Dog Stone which commemorates Carlo the Red Setter, a dog shot accidentally by his master while hunting on the 12 August 1864. Co-ordinates for the Dog Stone 51.45'15.58N 3.05'08.81W. Other notable tops include those of Mulfran (524m) which overlooks the town of Brynmawr and Mynydd James immediately east of the town of Blaina.
Mynydd Machen or Machen Mountain is a 362-metre-high (1,188 ft) hill lying between the town of Risca and the village of Machen in Caerphilly County Borough in south Wales. Its summit is crowned by a trig point and a mast.
Mynydd Llangynidr is a mountain in the Brecon Beacons National Park largely in the county of Powys, south Wales. Its southern slopes extend into the northernmost parts of the county borough of Blaenau Gwent. It is named from the village of Llangynidr which sits in the valley of the River Usk to the north of it. It is essentially an undulating plateau rising in the west to a height of 557m at Garn Fawr at OS grid ref SO 123151. A secondary high point is achieved at a point marked by a trig point at SO 147159. To the north the hill overlooks the valleys of Dyffryn Crawnon and Cwm Claisfer, themselves tributary valleys of the Usk. The shallow upper valley of the Ebbw River reaches into the plateau in the southeast whilst the upper reaches of the Sirhowy Valley and its tributary the Nant Trefil define its western margins. A further tributary, the Nant Milgatw, reaches in from the south whilst the sharp edge of Rassau Industrial Estate also defines a part of its southern margin. Passing east across the B4560, the hill merges with Mynydd Llangatwg which has a similar character.
Mynydd-y-glog is a hill just east of the village of Penderyn in the northern corner of the county borough of Rhondda Cynon Taff in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. Its summit plateau rises to a height of 389m / 1277 ft at OS grid ref SN 982088, a spot marked by a trig point. To its north lies the partly dry valley of Pant Sychbant which forms the eastern extension of Cwm Cadlan. Its southern slopes are drained by various streams which feed into the Afon Cynon.
Mynydd Carn-y-cefn is the name given to the broad ridge of high ground between the Ebbw Vale and the valley of the Ebbw Fach in the Valleys region of South Wales. It lies within the county borough of Blaenau Gwent, formerly Monmouthshire.
Cefn Manmoel is the name given to the broad ridge of high ground between the Sirhowy Valley and Ebbw Vale in the Valleys region of South Wales. It straddles the boundary between the unitary areas of Caerphilly and Blaenau Gwent.
Mynydd Merthyr is a broad ridge of high ground between Taff Vale and the Cwm Cynon in the Valleys region of South Wales. It forms the boundary between the unitary authorities of Rhondda Cynon Taff to the west and Merthyr Tydfil to the east.
Mynydd Cilfach-yr-encil attains a height of 445m at OS grid reference SO 079033 making it the high point of the broad ridge of high ground between Taff Vale and Cwm Bargod in the Valleys region of South Wales. It lies within the County Borough of Merthyr Tydfil.
Mynydd Bedwellte is the name given to the broad ridge of high ground between the Rhymney Valley and the Sirhowy Valley in the Valleys region of South Wales. It straddles the boundary of the unitary areas of Caerphilly and Blaenau Gwent.
Cefn y Brithdir is the name given to the broad ridge of high ground between the Rhymney Valley and Cwm Darran in the Valleys region of South Wales. It lies within the County Borough of Caerphilly.
The geology of Monmouthshire in southeast Wales largely consists of a thick series of sedimentary rocks of different types originating in the Silurian, Devonian, Carboniferous, Triassic and Jurassic periods.
Mynydd y Drum is a hill on the border between the county of Powys and Neath Port Talbot County Borough, south Wales. The summit of the hill is in Neath Port Talbot at 298m and lies towards the western end of a broad curving ridge, the larger part of which is in Powys. The eastern half of the hill is currently being opencasted for coal. The hill is sometimes referred to simply as The Drum.
Mynydd Meio is a 322-metre-high hill in the county borough of Caerphilly in South Wales. Parts of its western slopes fall within Rhondda Cynon Taf county borough. Its eastern slopes drop away to Cwm yr Aber between Caerphilly and Abertridwr and its western slopes to the valley of the Taf. The high point is just over 200 m north of the trig point which sits at 322 metres (1,056 ft) above sea-level.
Cefn Eglwysilan is a hill in South Wales, the twin 382m summits of which lie 2 km east of Pontypridd in Rhondda Cynon Taf county borough. Its eastern side lies within the community of Aber Valley in Caerphilly county borough. Like neighbouring Mynydd Eglwysilan, the hill is named after the hamlet of Eglwysilan, the church here being dedicated to an obscure saint Ilan. A wireless transmission station is sited on the more northerly of the two summits. The southerly one is crowned by a trig point.
Mynydd Eglwysilan is a 355-metre-high hill in the Caerphilly county borough in South Wales 3 km to the south of Nelson and a similar distance southwest of Ystrad Mynach. To its south is Senghenydd at the head of the Aber Valley. Like neighbouring Cefn Eglwysilan, the hill is named after the hamlet of Eglwysilan 4 km to the southwest, the church here being dedicated to an obscure Saint Ilan. Remains of a linear earthwork known as Senghenydd Dyke stretch across the southern side of the hill. It is considered to mark the edge of an extensive 13th-century deer park associated with nearby Caerphilly Castle.
Mynydd Twyn-glas is a sprawling 472-metre-high mountain extending into Caerphilly and Torfaen county boroughs in South Wales. It lies southwest of Pontypool, west of Cwmbran and east of Newbridge and taking the form of a rolling plateau the margins of which are defined by steep slopes, many of which are cloaked with conifer plantations. A broad shoulder extending south from the summit is known as Mynydd Maen whilst to the north is Mynydd Llwyd. The thickly afforested northern slopes of the hill drop down steeply into Cwm y Glyn.
Mynydd y Grug is a hill lying just west of the village of Cwmfelinfach and about 4 km to the northeast of Caerphilly in Caerphilly county borough in South Wales. Its summit was formerly at a height of around 358 m, but since the top has been covered by a large spoil heap and landscaped its height has now increased to 375 m, though some authorities take other values for the summit height. A number of ancient cairns are found along its edge overlooking the Sirhowy Valley, the slopes up from which are largely wooded.
Mynydd William Meyrick is a 535-metre-high hill straddling the boundary of Bridgend and Rhondda Cynon Taf county boroughs between the valley of the Rhondda Fawr and Ogmore Valley in South Wales. It takes the form of a broad northwest-southeast ridge with numerous broad shoulders extending to the east, south and west, each of which have different names and some of which constitute minor tops. Listed clockwise from the north these are; Mynydd Maendy, Mynydd Ton, Mynydd Bwllfa, Mynydd Pwllyrhebog, Mynydd Maes-teg, Mynydd y Gwair and Mynydd yr Aber. The summit of the entire massif is often referred to as Mynydd Ton. Its western sides are open moorland whilst its eastern sides have been afforested by the Forestry Commission.
