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Twyn y Post Cairns is a prehistoric platform cairn located in Wales and protected by Cadw as monument BR203. The monument was constructed on bedrock composed of Pridoli rocks—an undifferentiated sequence of mudstone, siltstone and sandstone laid down during the Pridoli epoch. This geological foundation provided a stable base for the cairn's construction, typical of how prehistoric builders selected firm ground for such substantial monuments.
Platform cairns represent an important category of Neolithic and Bronze Age funerary and ceremonial architecture. The form comprises a raised stone platform supporting a central cairn, often built to commemorate the dead or mark significant territorial and ritual locations. The specific arrangement and scale of Twyn y Post reflects local stone availability and building traditions of its period.
The monument's survival to the present day, despite weathering and potential historical disturbance, testifies to the substantial construction methods of prehistoric communities. Its protected status under Cadw ensures that this important archaeological resource remains available for future study and helps preserve evidence of early Welsh settlement patterns, burial practices and the landscape's long human history.
Twyn y Post Cairns is a scheduled monument protected by Cadw under reference BR203. View the official record →
Twyn y Post Cairns is a prehistoric platform cairn located in Wales and protected by Cadw as monument BR203. It is designated a Scheduled Ancient Monument by Cadw under reference BR203.
Twyn y Post Cairns dates from the prehistoric period, and is classified as a platform cairn. It is one of over 32,000 scheduled monuments protected across the UK.
Twyn y Post Cairns 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 BR203.
Several scheduled monuments lie within 10 km, including Gaer Fawr (3 km), Castell Madoc Ringwork (3.9 km), Castle Madoc Mound (4 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Twyn y Post Cairns'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.
Twyn y Post Cairns stands on Pridoli Rocks (Undifferentiated), bedrock that formed in the Pridoli. The rock here is mudstone, siltstone and sandstone.