Cefn Manmoel is the name given to the broad ridge of high ground between the

Sirhowy Valley The Sirhowy Valley ( ) is an industrialised valley in the eastern part of the Valleys region of Wales. It is named from the Sirhowy River () which runs through it. Its upper reaches are occupied by the town of Tredegar within the unitary area of ...

and

Ebbw Vale Ebbw Vale (; cy, Glynebwy) is a town at the head of the valley formed by the Ebbw Fawr tributary of the Ebbw River in Wales. It is the largest town and the administrative centre of Blaenau Gwent county borough. The Ebbw Vale and Brynmawr con ...

in the Valleys region of South

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

. It straddles the boundary between the unitary areas of Caerphilly and

Blaenau Gwent Blaenau Gwent (; ) is a county borough in the south-east of Wales. It borders the unitary authority areas of Monmouthshire and Torfaen to the east, Caerphilly to the west and Powys to the north. Its main towns are Abertillery, Brynmawr, E ...

. The NNW-SSE aligned ridge achieves a height of above sea-level at OS grid ref SO 166072. To the south it drops away to a broad saddle southeast of the village of Manmoel, beyond which lies Mynydd Pen-y-fan. Parts of both its eastern and western flanks are afforested with conifer plantations such as at Coed y Rhyd and at Coed y Llanerch.

Geology

The entire hill is composed of sandstones and mudstones dating from the

Carboniferous Period The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago (Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous ...

. There are also numerous

coal seam Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron fro ...

s within the sequence, most of which have been worked. The upper part of the hill including the summit plateau is formed from the

Pennant Sandstone The Pennant Measures is the traditional name for a sequence of sedimentary rocks of the South Wales Coalfield. They were also referred to as the Upper Coal Measures and assigned to the Westphalian 'C' and Westphalian 'D' stages of the Carbonifero ...

, a rock assigned to the Carboniferous Upper Coal Measures. The flanks of the hill owe their steepness in part to the action of

glacial ice A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

during the succession of

ice ages An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

. There are numerous abandoned quarries on the steep flanks of the ridge.

Access

Significant parts of the hill are moorland and have been mapped as

open country "Open Country" is a designation used for some UK access land. It was first defined under the National Parks and Access to the Countryside Act 1949 (and extended by the Countryside Act 1968), and was land over which an appropriate access agreeme ...

under the CRoW Act thus giving a right of access to walkers. Similar rights apply to some of the afforested areas. There are a number of

public footpath A footpath (also pedestrian way, walking trail, nature trail) is a type of thoroughfare that is intended for use only by pedestrians and not other forms of traffic such as motorized vehicles, bicycles and horses. They can be found in a w ...

s and other

public rights of way Right of way is the legal right, established by grant from a landowner or long usage (i.e. by prescription), to pass along a specific route through property belonging to another. A similar ''right of access'' also exists on land held by a gov ...

over the hill. The Sirhowy Valley Ridgeway Walk and the Ebbw Valley Walk follow some of these routes.Ordnance Survey 1:25,000 scale Explorer map series sheet 166 ''Rhondda & Merthyr Tydfil/Merthyr Tudful''

References

{{coord, 51.7521, -3.2094, dim:5000_region:GB, display=title Mountains and hills of Blaenau Gwent Mountains and hills of Caerphilly County Borough Caerphilly