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Offa's Dyke: Section South of Brymbo Colliery is an early medieval linear earthwork in Wales. Built between the 8th and early 9th centuries as a boundary between the Anglo-Saxon kingdom of Mercia and the Welsh kingdoms to the west, it represents one of Britain's most ambitious engineering projects of the period. This section, located above the Pennine and South Wales Middle Coal Measures Formation, survives as an earthen bank and ditch constructed through coalfield terrain. The underlying bedrock of mudstone, siltstone and sandstone would have presented significant challenges to the labourers who dug the ditch and threw up the bank, yet this section was nonetheless maintained as part of the wider defence or demarcation system. The monument is protected by Cadw under reference DE185 and forms part of a network of surviving segments that together trace the ambitious territorial ambitions of King Offa and his successors across the Welsh border landscape.
Offa's Dyke: Section South of Brymbo Colliery is a scheduled monument protected by Cadw under reference DE185. View the official record →
Offa's Dyke: Section South of Brymbo Colliery is an early medieval linear earthwork in Wales. It is designated a Scheduled Ancient Monument by Cadw under reference DE185.
Offa's Dyke: Section South of Brymbo Colliery 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 South of Brymbo Colliery 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 DE185.
Several scheduled monuments lie within 10 km, including Wat's Dyke: Section extending from Middle Sontley to Black Brook Bridge (7.8 km), Gardden Camp (8.5 km), Wat's Dyke: Section extending from Black Brook Bridge to Pentre-Clawdd (8.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Offa's Dyke: Section South of Brymbo Colliery'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 South of Brymbo Colliery 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.