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Craig y Llyn Mawr platform cairn and standing stone is a prehistoric platform cairn located in Wales and protected as an ancient monument by Cadw under reference MG328. The monument comprises a substantial artificial platform of stone, built directly upon the Wenlock rocks that underlie this site—sandstone and conglomerate bedrock laid down in the Wenlock period. Platform cairns of this type are characteristically Bronze Age monuments, constructed as burial or ceremonial structures with deliberately levelled bases.
The stone platform at Craig y Llyn Mawr is accompanied by a standing stone, a feature that suggests ritual or commemorative significance. The builders would have worked with locally available Wenlock stone, the durable interbedded sandstone and conglomerate that forms the immediate landscape. Such monuments often served to mark territorial claims or significant routes across upland terrain.
The monument survives as physical evidence of prehistoric land use and stone-working practices in Welsh uplands. The combination of platform cairn with standing stone reflects the monumental expression typical of Bronze Age communities, when such structures dominated the landscape as enduring markers of occupation and cultural identity.
Craig y Llyn Mawr platform cairn and standing stone is a scheduled monument protected by Cadw under reference MG328. View the official record →
Craig y Llyn Mawr platform cairn and standing stone is a prehistoric platform cairn located in Wales and protected as an ancient monument by Cadw under reference MG328.
Craig y Llyn Mawr platform cairn and standing stone 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.
Craig y Llyn Mawr platform cairn and standing stone 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 MG328.
Several scheduled monuments lie within 10 km, including Caersws Roman road (5.4 km), Caersws Roman Fort: Section of South Western Defences (5.9 km), Caersws Roman Fort and Vicus: section in southern part of vicus (6 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Craig y Llyn Mawr platform cairn and standing stone'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.
Craig y Llyn Mawr platform cairn and standing stone stands on Wenlock Rocks (Undifferentiated), bedrock that formed in the Wenlock. The rock here is sandstone and conglomerate, interbedded.