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Clawdd Mawr is a medieval linear earthwork in Wales, protected by Cadw under reference MG101. The monument consists of a substantial bank and ditch that cuts across the landscape, typical of defensive or boundary works constructed during the medieval period. Such earthworks commonly served to demarcate territorial limits, control movement across terrain, or provide defensive positions for settlements and administrative centres.
The earthwork is situated on bedrock composed of Caradoc Rocks, undifferentiated mudstone, siltstone and sandstone of Caradocian age. This geology would have influenced both the construction and survival of the monument, with the softer sedimentary rocks providing relatively manageable material for excavation whilst supporting the stability of the upcast banks that form the earthwork's principal visible feature today.
Clawdd Mawr's scale and linear form suggest it represents a substantial medieval engineering project, likely connected to political or military concerns of its period. The earthwork remains substantially intact and forms an important archaeological record of medieval land management and territorial organisation in Wales, preserved in the landscape as a physical manifestation of medieval administrative geography.
Clawdd Mawr is a scheduled monument protected by Cadw under reference MG101. View the official record →
Clawdd Mawr is a medieval linear earthwork in Wales, protected by Cadw under reference MG101.
Clawdd Mawr dates from the medieval period, and is classified as a linear earthwork. It is one of over 32,000 scheduled monuments protected across the UK.
Clawdd 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 MG101.
Several scheduled monuments lie within 10 km, including Cil Haul Barrow (0.4 km), Croes y Forwyn cairns (3.9 km), Afon y Dolau Gwynion kerb cairn (4.1 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Clawdd 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.
Clawdd Mawr stands on Caradoc Rocks (Undifferentiated), bedrock that formed in the Caradocian. The rock here is mudstone, siltstone and sandstone.