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Offa's Dyke: Cwm Section is a linear earthwork constructed during the early medieval period, forming part of the longer defensive boundary system that extends across the Welsh-English border. This section survives as a substantial bank and ditch aligned to follow the local topography, where it traverses terrain underlain by Ludlow Rocks—undifferentiated mudstones, siltstones and sandstones that would have presented considerable engineering challenges during its construction. The monument's preservation in this landscape demonstrates how the dyke's builders adapted their works to the underlying geology and natural contours of the borderland.
The earthwork was built as a territorial demarcation during the reign of Offa of Mercia in the late eighth century, marking a frontier between Welsh and English spheres of influence. The Cwm Section represents an important survival of this ambitious engineering project, which originally stretched for over 150 kilometres across the borderland. The monument's location on these distinctive geological strata, with their varied rock types resistant to erosion, has helped ensure the dyke's survival over more than a millennium.
Today the Cwm Section remains under the protection of Cadw, the Welsh heritage organisation, designated under reference MG151. The monument provides tangible evidence of early medieval territorial expansion and political authority, whilst its physical form continues to shape land use and landscape character in this border region of Wales.
Offa's Dyke: Cwm Section is a scheduled monument protected by Cadw under reference MG151. View the official record →
Offa's Dyke: Cwm Section is a linear earthwork constructed during the early medieval period, forming part of the longer defensive boundary system that extends across the Welsh-English border. It is designated a Scheduled Ancient Monument by Cadw under reference MG151.
Offa's Dyke: Cwm Section dates from the early medieval period, and is classified as a linear earthwork. It is one of over 32,000 scheduled monuments protected across the UK.
Offa's Dyke: Cwm Section 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 MG151.
Several scheduled monuments lie within 10 km, including Offa's Dyke: section 575m north west of Myndtown (6 km), Caer-Din Ring: a small enclosed Iron Age or Romano-British settlement, an adjacent ancient field boundary, round barrow and cultivation remains (6.1 km), Offa's Dyke: section 175m east of Cefn Bronydd (7.4 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Offa's Dyke: Cwm Section'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.
Offa's Dyke: Cwm Section stands on Ludlow Rocks (Undifferentiated), bedrock that formed in the Ludlow. The rock here is mudstone, siltstone and sandstone.