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Llyn y Tarw Cairn is a prehistoric round cairn situated in Wales and protected as a scheduled monument by Cadw under reference MG259. The monument consists of a mound of stone, characteristic of burial structures built across Britain and Ireland during the Neolithic and Bronze Age periods. Its construction would have been labour-intensive, requiring the gathering and stacking of stone blocks to create a durable memorial to the dead.
The cairn is positioned on bedrock of Wenlock Rocks—undifferentiated sandstone and conglomerate strata interbedded together—which formed during the Wenlock period of the Silurian era, approximately 430 million years ago. This underlying geology would have influenced both the availability of building stone and the landscape's natural drainage, important factors determining where prehistoric communities chose to locate their burial monuments.
Round cairns of this type served as communal or individual tombs, often reused over generations. The monument's survival to the present day, despite exposure to the Welsh climate and centuries of human activity across the landscape, testifies to the solid construction methods employed by its builders. Its protected status ensures that this record of prehistoric funerary practice remains available for study and public appreciation.
Llyn y Tarw Cairn is a scheduled monument protected by Cadw under reference MG259. View the official record →
Llyn y Tarw Cairn is a prehistoric round cairn situated in Wales and protected as a scheduled monument by Cadw under reference MG259.
Llyn y Tarw Cairn 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.
Llyn y Tarw 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 MG259.
Several scheduled monuments lie within 10 km, including Roman Earthwork NE of Caersws (revealed by aerial photography) (5.4 km), Caersws Roman Site (5.6 km), Caersws Roman Fort: Section of South Western Defences (5.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Llyn y Tarw 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.
Llyn y Tarw Cairn stands on Wenlock Rocks (Undifferentiated), bedrock that formed in the Wenlock. The rock here is sandstone and conglomerate, interbedded.