© Mapbox · © OpenStreetMap contributors · Boundary data © Cadw
Merlins Hill Hillfort is a prehistoric hillfort located in Wales and protected by Cadw under reference CM231. The site commands its landscape from bedrock of Llanvirn Rocks, undifferentiated sedimentary deposits formed during the Whiterock period, composed of mudstone, siltstone and sandstone. This solid foundation provided a stable platform for the substantial earthworks characteristic of Iron Age defensive settlements.
The hillfort's strategic positioning reflects the careful site selection practised by prehistoric communities, who chose elevated ground to maximise visibility across surrounding terrain. The underlying geology, typical of the Welsh landscape, would have presented both opportunities and constraints for construction. The relatively stable bedrock of mixed sedimentary stones would have supported timber ramparts and permitted the digging of ditches and internal features.
Hillforts of this type represent the most monumental works of Iron Age Britain and Ireland, serving as communal focal points for settlement, defence and possibly ceremonial gatherings. Merlins Hill's survival to the present day, and its protection as a scheduled monument, acknowledges its significance as evidence of prehistoric social organisation and territorial control within the Welsh uplands.
Merlins Hill Hillfort is a scheduled monument protected by Cadw under reference CM231. View the official record →
Merlins Hill Hillfort is a prehistoric hillfort located in Wales and protected by Cadw under reference CM231.
Merlins Hill Hillfort dates from the prehistoric period, and is classified as a hillfort. It is one of over 32,000 scheduled monuments protected across the UK.
Merlins Hill Hillfort 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 CM231.
Several scheduled monuments lie within 10 km, including Carmarthen Roman Fort (part of) (4.2 km), Carmarthen Castle (4.4 km), The Bulwarks (Civil War) (4.8 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Merlins Hill Hillfort'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.
Merlins Hill Hillfort stands on Llanvirn Rocks (Undifferentiated), bedrock that formed in the Whiterock. The rock here is mudstone, siltstone and sandstone.