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Llyn Gwyn Earthwork is an unclassified earthwork of uncertain origin and date, located in Wales and protected as a scheduled monument under Cadw reference RD079. The monument sits upon bedrock of Ashgill age, composed of mudstone, siltstone and sandstone that underlies much of this part of Wales. The geological foundation provided by these sedimentary rocks is typical of the region's Ordovician landscape.
The earthwork's true character and construction date remain undetermined, placing it among Wales's more enigmatic archaeological features. Without diagnostic features or recorded excavation, it cannot be securely assigned to any particular period, though its survival as an upstanding earthwork suggests substantial original construction. The absence of clear classification reflects the limitations of surface inspection alone in understanding such monuments.
The site's protection under Cadw indicates recognition of its potential archaeological significance, whether as a defensive work, territorial boundary, or settlement-related feature. The preservation of Llyn Gwyn as a scheduled monument ensures that future archaeological investigation may eventually clarify its purpose and date, contributing to understanding of Wales's human landscape during whichever period it was created.
Llyn Gwyn Earthwork is a scheduled monument protected by Cadw under reference RD079. View the official record →
Llyn Gwyn Earthwork is an unclassified earthwork of uncertain origin and date, located in Wales and protected as a scheduled monument under Cadw reference RD079.
Llyn Gwyn Earthwork dates from the unknown period, and is classified as a earthwork (unclassified). It is one of over 32,000 scheduled monuments protected across the UK.
Llyn Gwyn Earthwork 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 RD079.
Several scheduled monuments lie within 10 km, including Pen-llys Earthwork (6.7 km), Pen-y-bont Standing Stone (7 km), Caer Du (7.3 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Llyn Gwyn Earthwork'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.
Llyn Gwyn Earthwork stands on Ashgill Rocks (Undifferentiated), bedrock that formed in the Ashgill. The rock here is mudstone, siltstone and sandstone.