Ancient Monuments

History on the Ground

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Pen Allt-mawr platform cairn

A Scheduled Monument in Llanfihangel Cwmdu with Bwlch and Cathedine (Llanfihangel Cwm Du gyda Bwlch a Chathedin), Powys

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Latitude: 51.9119 / 51°54'42"N

Longitude: -3.1544 / 3°9'15"W

OS Eastings: 320691

OS Northings: 224332

OS Grid: SO206243

Mapcode National: GBR F0.PL6B

Mapcode Global: VH6C9.86RQ

Entry Name: Pen Allt-mawr platform cairn

Scheduled Date: 3 February 2006

Source: Cadw

Source ID: 1091

Cadw Legacy ID: BR305

Schedule Class: Religious, Ritual and Funerary

Category: Platform Cairn

Period: Prehistoric

County: Powys

Community: Llanfihangel Cwmdu with Bwlch and Cathedine (Llanfihangel Cwm Du gyda Bwlch a Chathedin)

Traditional County: Brecknockshire


The monument comprises the remains of a burial cairn, probably dating to the Bronze Age (c.2300 BC - 800 BC) and situated in open moorland on the leading N-facing edge of the summit of Pen Allt-mawr. The stone-built cairn is roughly circular on plan and measures about 13.5m in diameter. The cairn was possibly originally a platform cairn - the cairn displays no evidence of original 'bulk', while elements of a ring bank (an earth and stone bank 1.5m in thickness) are occasionally visible around the cairn edges. The presence of two further possible platform cairns on the ridge, at Pen Cerrig-calch (BR304) and Pen Gloch-y-pibwr (BR307), supports this interpretation.

The monument is of national importance for its potential to enhance our knowledge of prehistoric burial and ritual practices. The well-preserved monument is an important relic of a prehistoric funerary and ritual landscape and retains significant archaeological potential, with a strong probability of the presence of both intact burial or ritual deposits and environmental and structural evidence. The likelihood that the cairn is an example of a more unusual structural class of cairn, the platform cairn, further increases its importance.

The scheduled area comprises the remains described and an area around them within which related evidence may be expected to survive. It is circular and measures 22m in diameter.

Source: Cadw

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