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Cored Gwyrfai Fish Weir is a medieval fish weir located in Wales, constructed to exploit the flow of water through a river channel in order to trap and catch migrating fish. The structure exemplifies a widespread practice of river management throughout medieval Britain and Wales, where weirs served both subsistence and commercial purposes for local communities and manorial lords. Built upon bedrock of Precambrian mica schist, the weir sits upon ancient metamorphic foundations that have remained substantially unchanged since the earth's earliest geological periods.
The weir's construction reflects the practical engineering knowledge of medieval Welsh builders, who selected this location on the river to harness natural water dynamics. The underlying geology of mica schist would have provided a relatively stable base for the structure, though such ancient bedrock typically weathers into uneven surfaces that required careful stonework to create an effective barrier. The design of fish weirs of this period generally involved angled structures or chambers that guided fish into holding areas from which they could be easily collected.
The monument is protected by Cadw, the Welsh heritage organisation, under the reference number CN334, ensuring its preservation as evidence of medieval riverine resource management. Such weirs remain important archaeological records of how medieval communities interacted with their natural landscape, demonstrating the sophistication of their hydraulic engineering within the constraints of available materials and technology.
Cored Gwyrfai Fish Weir is a scheduled monument protected by Cadw under reference CN334. View the official record →
Cored Gwyrfai Fish Weir is a medieval fish weir located in Wales, constructed to exploit the flow of water through a river channel in order to trap and catch migrating fish. It is designated a Scheduled Ancient Monument by Cadw under reference CN334.
Cored Gwyrfai Fish Weir dates from the medieval period, and is classified as a fish weir. It is one of over 32,000 scheduled monuments protected across the UK.
Cored Gwyrfai Fish Weir 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 CN334.
Several scheduled monuments lie within 10 km, including Enclosed Hut Circle Settlement West of Votglas (8.2 km), Blaen y Cae Slate Quarry (8.6 km), Caer Engan (8.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Cored Gwyrfai Fish Weir'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.
Cored Gwyrfai Fish Weir stands on Precambrian mica, bedrock that formed in the Precambrian. The rock here is mica schist; undifferentiated metamorphic.