© Mapbox · © OpenStreetMap contributors · Boundary data © Cadw
Pen Twr ring cairn is a prehistoric monument consisting of a roughly circular arrangement of stones forming a low raised platform. Located in Wales, it stands on bedrock composed of Ashgill Rocks—a sequence of mudstone, siltstone and sandstone deposited during the Ashgill period in the Ordovician epoch. The underlying geology of darker, compact sedimentary stone would have been exposed in the local landscape when the cairn was constructed, potentially influencing the choice of materials available for building. Ring cairns of this type are typically dated to the Bronze Age and are thought to have served ritual or ceremonial purposes, though their exact function remains debated among archaeologists.
The monument is protected by Cadw, the Welsh Historic Monuments organisation, under reference BR371. The site's preservation reflects its significance to understanding prehistoric funerary and ceremonial practices in Wales. The cairn's form—a circular perimeter rather than a central mound—distinguishes it from other Bronze Age burial cairns found across the Welsh uplands. Like many such monuments, Pen Twr has endured considerable time-weathering, yet its basic structure remains visible in the landscape, testament to the durability of its dry-stone construction.
Pen Twr ring cairn is a scheduled monument protected by Cadw under reference BR371. View the official record →
Pen Twr ring cairn is a prehistoric monument consisting of a roughly circular arrangement of stones forming a low raised platform. It is designated a Scheduled Ancient Monument by Cadw under reference BR371.
Pen Twr ring cairn dates from the prehistoric period, and is classified as a ring cairn. It is one of over 32,000 scheduled monuments protected across the UK.
Pen Twr ring 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 BR371.
Several scheduled monuments lie within 10 km, including Banc Paderau Round Cairn (2 km), Pen-y-Garn-Goch Long Barrow (2.2 km), Fforest Castle Mound (2.4 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Pen Twr ring 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.
Pen Twr ring cairn stands on Ashgill Rocks (Undifferentiated), bedrock that formed in the Ashgill. The rock here is mudstone, siltstone and sandstone.