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Castell Pen-yr-Allt is a medieval castle situated in Wales and protected by Cadw as a scheduled monument. The site occupies elevated ground underlain by Ashgill Rocks, a formation of mudstone, siltstone and sandstone dating to the Ashgill age. This solid geological foundation provided a stable base for the castle's construction and defensive position.
The castle exemplifies medieval Welsh fortification strategy, positioned to command its surrounding landscape. The Ashgill bedrock, composed of alternating layers of fine-grained sediments, would have offered both practical advantages for building foundations and natural resistance to erosion on the exposed hillside. The solid geology beneath the site contrasts with lower-lying areas of softer drift deposits that characterise much of the Welsh lowlands.
As a scheduled monument under Cadw's protection, Castell Pen-yr-Allt represents an important survival of medieval military architecture in Wales. The castle's positioning on this Ashgill outcrop reflects the practical considerations of medieval builders, who selected sites offering natural defensibility and accessible stone for construction, combining topographic advantage with the available local geology.
Castell Pen-yr-Allt is a scheduled monument protected by Cadw under reference PE169. View the official record →
Castell Pen-yr-Allt is a medieval castle situated in Wales and protected by Cadw as a scheduled monument. It is designated a Scheduled Ancient Monument by Cadw under reference PE169.
Castell Pen-yr-Allt dates from the medieval period, and is classified as a castle. It is one of over 32,000 scheduled monuments protected across the UK.
Castell Pen-yr-Allt 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 PE169.
Several scheduled monuments lie within 10 km, including Corn Drying Kiln 130m E of Mirianog-Ganol (7.8 km), Foel Drygarn Camp (8.5 km), Carn Alw Hillfort (8.5 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Castell Pen-yr-Allt'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.
Castell Pen-yr-Allt stands on Ashgill Rocks (Undifferentiated), bedrock that formed in the Ashgill. The rock here is mudstone, siltstone and sandstone.