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Offa's Dyke: Cadwgan Hall Section is an early medieval linear earthwork forming part of the substantial defensive frontier constructed between England and Wales. This section of the dyke extends from the River Clywedog to the railway and represents one of the most significant archaeological monuments of the period. Built predominantly during the reign of Offa, King of Mercia in the late eighth century, the earthwork consists of a substantial bank with external ditch, engineered to command the landscape and regulate movement across the border.
The monument sits upon bedrock of the Pennine and South Wales Middle Coal Measures Formation, comprising mudstone, siltstone, sandstone, coal, ironstone and ferricrete. This Carboniferous geology shaped both the dyke's construction and its landscape context, with the underlying strata influencing drainage and soil conditions along the ridge line. The Clywedog valley to the west provides a natural reference point for this section's extent.
The Cadwgan Hall section remains substantially preserved and forms part of the larger Offa's Dyke National Trail. It is protected by Cadw, the Welsh heritage preservation authority, under the scheduled monument reference DE132, recognising its importance as a rare surviving example of large-scale medieval earthwork engineering and its significance to understanding Anglo-Welsh political boundaries in the early medieval period.
Offa's Dyke: Cadwgan Hall Section, extending from River Clywedog to the Railway is a scheduled monument protected by Cadw under reference DE132. View the official record →
Offa's Dyke: Cadwgan Hall Section is an early medieval linear earthwork forming part of the substantial defensive frontier constructed between England and Wales. It is designated a Scheduled Ancient Monument by Cadw under reference DE132.
Offa's Dyke: Cadwgan Hall Section, extending from River Clywedog to the Railway 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: Cadwgan Hall Section, extending from River Clywedog to the Railway 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 DE132.
Several scheduled monuments lie within 10 km, including Offa's Dyke: Section SW from Tatham Bridge (5.1 km), Wynnstay Colliery Walker Fan House (5.3 km), Wynnstay Colliery Winding Engine House (5.4 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Offa's Dyke: Cadwgan Hall Section, extending from River Clywedog to the Railway'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: Cadwgan Hall Section, extending from River Clywedog to the Railway stands on Pennine Middle Coal Measures Formation And South Wales Middle Coal Measures Formation (Undifferentiated), bedrock that formed in the Moscovian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.