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Offa's Dyke: Section S from Cae Llewellyn is an early medieval linear earthwork stretching across the Welsh landscape. Constructed during the 8th century, this section of the famous defensive frontier was built across ground underlain by the Middle Coal Measures formations—ancient sedimentary deposits of mudstone, siltstone and sandstone interspersed with coal seams and ironstone, laid down during the Moscovian period. The earthwork's construction exploited the natural topography of this coalfield geology, with the ditch and bank aligned to follow the terrain and take advantage of harder ironstone-cemented layers where they occurred in the underlying bedrock.
This section represents part of the most substantial linear earthwork surviving from early medieval Britain, stretching for many miles along the Welsh border. The monument is protected by Cadw, the Welsh heritage organisation, under reference DE110, recognising its national significance. Today, the surviving earthwork remains a prominent landscape feature, its scale and engineering reflecting the considerable labour investment required to construct such a monumental frontier demarcation during the early medieval period.
Offa's Dyke: Section S from Cae Llewellyn is a scheduled monument protected by Cadw under reference DE110. View the official record →
Offa's Dyke: Section S from Cae Llewellyn is an early medieval linear earthwork stretching across the Welsh landscape. It is designated a Scheduled Ancient Monument by Cadw under reference DE110.
Offa's Dyke: Section S from Cae Llewellyn 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: Section S from Cae Llewellyn 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 DE110.
Several scheduled monuments lie within 10 km, including Wat's Dyke: Section extending from Middle Sontley to Black Brook Bridge (7.1 km), Gardden Camp (7.8 km), Wat's Dyke: Section extending from Black Brook Bridge to Pentre-Clawdd (8 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Offa's Dyke: Section S from Cae Llewellyn'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: Section S from Cae Llewellyn 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.