Ancient Monuments

History on the Ground

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Onllwyn Round Cairn

A Scheduled Monument in Cyfarthfa, Merthyr Tydfil (Merthyr Tudful)

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Latitude: 51.7718 / 51°46'18"N

Longitude: -3.4566 / 3°27'23"W

OS Eastings: 299589

OS Northings: 209130

OS Grid: SN995091

Mapcode National: GBR YL.ZH7M

Mapcode Global: VH6CQ.1QGL

Entry Name: Onllwyn Round Cairn

Scheduled Date: 6 July 2000

Source: Cadw

Source ID: 1599

Cadw Legacy ID: GM530

Schedule Class: Religious, Ritual and Funerary

Category: Round cairn

Period: Prehistoric

County: Merthyr Tydfil (Merthyr Tudful)

Community: Cyfarthfa

Traditional County: Brecknockshire


The monument comprises the remains of a burial cairn probably dating to the Bronze Age (c. 2300 - 800 BC). The cairn measures c. 7m in diameter and stands 0.75m high.

The monument is of national importance for its potential to enhance our knowledge of prehistoric burial and ritual practices. The 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, 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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