Gilwern Hill is a 441 m high hill 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 ...

, south of the village of

Gilwern Gilwern is a village within the Brecon Beacons National Park in Monmouthshire, Wales. Historically in Brecknockshire, it extends to either side of the River Clydach on the south side of the Usk valley. Its position beside the Monmouthshire a ...

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 ...

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 ...

. It lies west of the

Blorenge 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 plat ...

. The hill is a

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...

Geology

Gilwern Hill is formed from a series of rock strata of

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

age, each of which dip moderately southwards. The summit plateau is formed from

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

s - the

Farewell Rock The Farewell Rock is the name given to a series of sandstones at the boundary of the Coal Measures with the underlying Marros Group in South Wales. Once thought to be a single sandstone, it is now accepted that the same name has been applied to s ...

and the

Twrch Sandstone The Marros Group is the name given to a suite of rocks of Namurian age laid down during the Carboniferous period (geology), Period in South Wales. These rocks were formerly known as the Millstone Grit, Millstone Grit Series but are now distinguish ...

which overlie the Carboniferous Limestone. The latter has been extensively quarried around the eastern, northern and western margins of the hill where it is exposed. Derelict tramways are in evidence in connection with the working of these quarries for limestone in connection with iron and steel-smelting.British Geological Survey 1:50K map sheet 232 ''Abergavenny''

Access and recreation

Virtually the entire hill is designated as

open country "Open Country" is a designation used for some access land in England and Wales. 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 appropr ...

and so access is therefore available freely to walkers. A minor road wraps around its southern and western margins whilst a couple of public footpaths and a

restricted byway A byway in the United Kingdom is a track, often rural, which is too minor to be called a road. These routes are often unsurfaced, typically having the appearance of ' green lanes'. Despite this, it is legal (but may not be physically possible) t ...

cross the northern and eastern slopes of the hill. The quarries provide a minor venue for

rock climbing Rock climbing is a climbing sports discipline that involves ascending climbing routes, routes consisting of natural rock in an outdoor environment, or on artificial resin climbing walls in a mostly indoor environment. Routes are documented in c ...

References

{{reflist, 30em

External links

Historic landscape of Gilwern Hill

UKC Rock Climbing info on Gilwern Hill
Sites of Special Scientific Interest in Monmouthshire Mountains and hills of Monmouthshire