Ancient Monuments

History on the Ground

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Twyn y Post Cairns

A Scheduled Monument in Merthyr Cynog, Powys

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Latitude: 52.0578 / 52°3'28"N

Longitude: -3.4188 / 3°25'7"W

OS Eastings: 302820

OS Northings: 240887

OS Grid: SO028408

Mapcode National: GBR YN.DDMC

Mapcode Global: VH6BC.PJHT

Entry Name: Twyn y Post Cairns

Scheduled Date: 22 March 1994

Source: Cadw

Source ID: 766

Cadw Legacy ID: BR203

Schedule Class: Religious, Ritual and Funerary

Category: Platform Cairn

Period: Prehistoric

County: Powys

Community: Merthyr Cynog

Traditional County: Brecknockshire


The monument comprises the remains of three cairns, which probably date to the Bronze Age (c. 2300 - 800 BC). The cairns are located adjacent to each other on a level hilltop above the upper reaches of the Honddu valley. The NW cairn comprises a flat-topped stone round cairn 11m in diameter and 0.4m high. The central cairn is located 15m to the SSE and comprises a small ring cairn 8m in diameter, with a surviving bank 2.5m wide and 0.4m high. The bank tapers off to the E and has been destroyed in the NE quadrant. The SE cairn comprises a small ring cairn 12m in diameter with a surviving bank around 3m wide at the base and up to 1.5m wide on top. There is an inner ditch encircling the central dome which is 5m in diameter at the base. There is a small hollow on the W side and a small gap in the SE side of the outer bank.

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. Cairns 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

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