Ancient Monuments

History on the Ground

This site is entirely user-supported. See how you can help.

Twyn-Yr-Oerfel Round Barrows

A Scheduled Monument in Ynysddu (Ynys-ddu), Caerphilly (Caerffili)

We don't have any photos of this monument yet. Why don't you be the first to send us one?

Upload Photo »

Approximate Location Map
Large Map »

If Google Street View is available, the image is from the best available vantage point looking, if possible, towards the location of the monument. Where it is not available, the satellite view is shown instead.


Latitude: 51.6087 / 51°36'31"N

Longitude: -3.1817 / 3°10'54"W

OS Eastings: 318263

OS Northings: 190644

OS Grid: ST182906

Mapcode National: GBR HY.9SGQ

Mapcode Global: VH6DM.STTN

Entry Name: Twyn-Yr-Oerfel Round Barrows

Scheduled Date: 18 December 1957

Source: Cadw

Source ID: 2975

Cadw Legacy ID: MM070

Schedule Class: Religious, Ritual and Funerary

Category: Round barrow

Period: Prehistoric

County: Caerphilly (Caerffili)

Community: Ynysddu (Ynys-ddu)

Traditional County: Monmouthshire


The monument comprises the remains of two earthen built round barrows, burial monuments which probably date to the Bronze Age (c. 2300 - 800 BC). The eastern barrow is circular in plan, 10m in diameter, up to 1.3m high with steep sides and has a 0.4m deep depression in the centre. The western barrow is circular in plan, 15m in diameter, and up to 1.8m high with steep sides. The barrows, constructed on the top of a natural rock outcrop on a high ridge in moorland overlooking the Sirhowy Valley, are grass covered. The barrows are likely to have covered a single primary burial, cut into the bedrock, either in a pit or a cist. Secondary burials, probably cremations, could have been dug into the barrows during the Bronze Age, placed within the body of the monument in pots.

The monument is of national importance for its potential to enhance our knowledge of prehistoric burial and ritual practices. The features are an important relic of a prehistoric funerary and ritual landscape and retain significant archaeological potential. There is a strong probability of the presence of both intact ritual and burial deposits, together with environmental and structural evidence. Barrows may be part of a larger cluster of monuments and their importance can further enhanced by their group value.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

Other nearby scheduled monuments is an independent online resource and is not associated with any government department. All government data published here is used under licence. Please do not contact for any queries related to any individual ancient or schedued monument, planning permission related to scheduled monuments or the scheduling process itself. is a Good Stuff website.