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Castell Mawr is a prehistoric hillfort situated in Wales and protected by Cadw under reference PE172. The monument occupies a naturally defensible position where the underlying bedrock comprises Caradoc Rocks, a mixed sequence of mudstone, siltstone and sandstone laid down during the Caradocian period. This geology has weathered to create the terrain upon which the fort's defences were constructed, with the varied rock types contributing to the landscape's topographical character.
The fort follows the typical plan of Iron Age hillforts in Wales, with ramparts and ditches following the contours of the hilltop to command views across the surrounding countryside. The Caradoc Rocks bedrock, though harder than pure mudstone, would have presented significant quarrying challenges for the construction of such substantial earthworks, requiring considerable labour investment to extract stone and shape the defences.
Castell Mawr represents an important element of the prehistoric settlement pattern in Wales. The choice of this particular location reflects Iron Age strategic thinking: the natural defensive advantages of the site combined with command of local resources and communication routes. The monument survives as an archaeological and landscape feature, recording the Iron Age occupation and organisation of this part of Wales within the broader context of British prehistoric settlement.
Castell Mawr is a scheduled monument protected by Cadw under reference PE172. View the official record →
Castell Mawr is a prehistoric hillfort situated in Wales and protected by Cadw under reference PE172.
Castell Mawr dates from the prehistoric period, and is classified as a hillfort. It is one of over 32,000 scheduled monuments protected across the UK.
Castell Mawr 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 PE172.
Several scheduled monuments lie within 10 km, including Cnwc Round Cairns (8.2 km), Mynydd Crwn standing stone (8.4 km), Gors Fawr Stone Circle (8.5 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Castell Mawr'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 Mawr stands on Caradoc Rocks (Undifferentiated), bedrock that formed in the Caradocian. The rock here is mudstone, siltstone and sandstone.