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Offa's Dyke: Section N & S of Plas-Offa is an early medieval linear earthwork forming part of the frontier dyke constructed across the Welsh borderland. Built in the late eighth century, it extends northward and southward from Plas-Offa, cutting through terrain underlain by Millstone Grit Group bedrock. This geological foundation of mudstone, siltstone and sandstone, formed during the Namurian period, provided firm ground for the substantial earthwork's construction and continues to shape the landscape's topography today.
The dyke at this location represents a significant engineering achievement of the Anglo-Saxon period, erected to demarcate territorial boundaries between the kingdom of Mercia and the Welsh principalities. The section's survival as an upstanding feature owes much to the stable geology beneath, which supported the formation of a durable bank and ditch system. The monument's preservation across centuries reflects both the robustness of its original construction and the relatively undisturbed character of this stretch of borderland.
Protected by Cadw under reference DE138, this section of Offa's Dyke remains a prominent landscape feature and important archaeological record. It provides evidence of early medieval settlement patterns, territorial control and engineering capability. The earthwork's course through this terrain illustrates how medieval builders adapted their construction to local geological conditions whilst maintaining the dyke's strategic effectiveness as a linear frontier defence.
Offa's Dyke: Section N & S of Plas-Offa is a scheduled monument protected by Cadw under reference DE138. View the official record →
Offa's Dyke: Section N & S of Plas-Offa is an early medieval linear earthwork forming part of the frontier dyke constructed across the Welsh borderland. It is designated a Scheduled Ancient Monument by Cadw under reference DE138.
Offa's Dyke: Section N & S of Plas-Offa 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 N & S of Plas-Offa 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 DE138.
Several scheduled monuments lie within 10 km, including Orseddwen cairn (7.3 km), Wat's Dyke: 140m long section, 370m south west of Gobowen Station (7.7 km), Wat's Dyke: 180m long section, 170m east of Pentre-wern (7.8 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Offa's Dyke: Section N & S of Plas-Offa'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 N & S of Plas-Offa stands on Millstone Grit Group [See Also Migr], bedrock that formed in the Namurian. The rock here is mudstone, siltstone and sandstone.