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Carn Pen-Rhiw-Ddu is a prehistoric round cairn situated in Wales, constructed atop bedrock of Dinantian limestone, sandstone and argillaceous rocks. The monument sits within a geological setting typical of the Carboniferous period, where such stone-built structures were erected in upland and marginal landscapes. Round cairns of this kind served as burial monuments during the Bronze Age, constructed by heaping stone to mark significant graves and ceremonial spaces.
The cairn's construction would have utilised locally available stone from the Dinantian bedrock and surface scree. The limestone-rich geology of the site provided abundant building material, whilst the elevated terrain afforded visibility and prominence in the surrounding landscape. Such positioning was characteristic of prehistoric funerary monuments, allowing these markers to command attention across the valleys and ridges of early British communities.
Carn Pen-Rhiw-Ddu is protected by Cadw under reference CM172, recognition of its significance as a surviving prehistoric monument. Despite the passage of millennia and weathering of its stone, the cairn remains a tangible record of Bronze Age burial practices and the relationship between these ancient communities and their landscape. The monument contributes to understanding how prehistoric societies chose and used upland terrain in Wales.
Carn Pen-Rhiw-Ddu is a scheduled monument protected by Cadw under reference CM172. View the official record →
Carn Pen-Rhiw-Ddu is a prehistoric round cairn situated in Wales, constructed atop bedrock of Dinantian limestone, sandstone and argillaceous rocks. It is designated a Scheduled Ancient Monument by Cadw under reference CM172.
Carn Pen-Rhiw-Ddu dates from the prehistoric period, and is classified as a round cairn. It is one of over 32,000 scheduled monuments protected across the UK.
Carn Pen-Rhiw-Ddu is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is CM172.
Several scheduled monuments lie within 10 km, including Llwyncwmstabl round cairn (6.3 km), Banc Crucorford round cairn (6.5 km), Dorwen standing stone (6.5 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Carn Pen-Rhiw-Ddu's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Carn Pen-Rhiw-Ddu stands on Dinantian Rocks (Undifferentiated), bedrock that formed in the Mississippian. The rock here is limestone with subordinate sandstone and argillaceous rocks.