The Hatterrall Ridge is a ridge in the Black Mountains

Black Mountains, Wales

The Black Mountains are a group of hills spread across parts of Powys and Monmouthshire in southeast Wales, and extending across the national border into Herefordshire, England. They are the easternmost of the four ranges of hills that comprise the Brecon Beacons National Park, and are frequently...

 forming the border between Powys

Powys

Powys is a local-government county and preserved county in Wales.-Geography:Powys covers the historic counties of Montgomeryshire and Radnorshire, most of Brecknockshire , and a small part of Denbighshire — an area of 5,179 km², making it the largest county in Wales by land area.It is...

 and Monmouthshire

Monmouthshire

Monmouthshire is a county in south east Wales. The name derives from the historic county of Monmouthshire which covered a much larger area. The largest town is Abergavenny. There are many castles in Monmouthshire .-Historic county:...

 in Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

 and Herefordshire

Herefordshire

Herefordshire is a historic and ceremonial county in the West Midlands region of England. For Eurostat purposes it is a NUTS 3 region and is one of three counties that comprise the "Herefordshire, Worcestershire and Gloucestershire" NUTS 2 region. It also forms a unitary district known as the...

 in England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The ridge is about 10 miles (16 km) long, and is followed by the Offa's Dyke Path

Offa's Dyke Path

Offa's Dyke Path is a long distance footpath along the Welsh-English border. Opened in 1971, it is one of Britain's premier National Trails and draws walkers from throughout the world...

. On the west side of the ridge is the Vale of Ewyas

Vale of Ewyas

The Vale of Ewyas is the steeply-sided and secluded valley of the Afon Honddu, in the Black Mountains of south Wales and within the Brecon Beacons National Park. As well as its outstanding beauty, it is known for the ruins of Llanthony Priory, and for several noteworthy churches such as those at...

, and on the east side is the Olchon Valley. The western side of the ridge falls within the Brecon Beacons National Park.

The highest point on the ridge is Black Mountain

Black Mountain (hill)

Twyn Llech also known as Black Mountain is a mountain in the Black Mountains . It is the only Marilyn to fall exactly on the Welsh-English border, straddling Powys and Herefordshire...

 (elevation 703 m), near its northern end. Hatterrall Hill

Hatterrall Hill

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...

(elevation 531 m) is near the southern end of the ridge. The hill is common land grazed by sheep, ponies and cattle.