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Mynydd Bychan platform cairn is a prehistoric ritual or ceremonial monument built on the high moorland of Wales. The cairn consists of a substantial rubble platform constructed from locally derived stone, typical of the platform cairn tradition found across upland Britain during the Bronze Age. The builders selected this elevated location deliberately, creating a level artificial surface that would have been visible across the surrounding landscape and used for gatherings, ceremonies or commemorative purposes.
The monument sits directly on bedrock composed of Lower Devonian rocks—mudstone, siltstone and sandstone formed over 400 million years ago. This geology provided the stone necessary for cairn construction, and the natural slope of the moorland offered an ideal location for platform building. The summit position commands views across the Welsh valleys and ridges, emphasising the cairn's role as a focal point in the Bronze Age ritual landscape.
Mynydd Bychan platform cairn is protected as a scheduled monument by Cadw, the Welsh heritage agency, under reference BR320. The site survives today as substantial earthwork remains, preserving evidence of prehistoric ceremonial practices and landscape use that shaped the Welsh uplands during the Bronze Age.
Mynydd Bychan platform cairn is a scheduled monument protected by Cadw under reference BR320. View the official record →
Mynydd Bychan platform cairn is a prehistoric ritual or ceremonial monument built on the high moorland of Wales. It is designated a Scheduled Ancient Monument by Cadw under reference BR320.
Mynydd Bychan platform cairn 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.
Mynydd Bychan platform cairn 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 BR320.
Several scheduled monuments lie within 10 km, including Inscribed Stone in Church (8.3 km), Bipartite enclosure 1km SSE of Pen Allt-Mawr, Cwm Banw (8.7 km), Pen Gloch-y-pibwr, platform cairn on S end of (8.8 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Mynydd Bychan platform cairn'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.
Mynydd Bychan platform cairn stands on Lower Devonian Rocks (Undifferentiated), bedrock that formed in the Early Devonian. The rock here is mudstone, siltstone and sandstone.