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Oystermouth Castle is a medieval fortress situated on a prominent headland overlooking Swansea Bay in Glamorgan, Wales. The castle was founded in the early twelfth century by the Norman de Breos family and developed substantially during the thirteenth and fourteenth centuries, with its defences comprising a stone keep, curtain walls, and multiple towers arranged across two baileys. The site reflects the strategic importance of coastal defence during the medieval period and demonstrates the architectural evolution typical of Welsh marcher lordships under Norman control. Though partially ruined, the castle retains significant structural remains including parts of its defensive walls and towers, making it an important example of Norman military architecture in South Wales.
Oystermouth Castle is a scheduled monument protected by Cadw under reference GM007. View the official record →
Oystermouth Castle is a medieval fortress situated on a prominent headland overlooking Swansea Bay in Glamorgan, Wales. It is designated a Scheduled Ancient Monument by Cadw under reference GM007.
Oystermouth Castle dates from the medieval period, and is classified as a castle. It is one of over 32,000 scheduled monuments protected across the UK.
Oystermouth Castle 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 GM007.
Several scheduled monuments lie within 10 km, including St Peter's Chapel & Well, Caswell Bay (2.3 km), Clyne Wood Arsenic & Copper Works (2.4 km), Caswell Cliff Fort (2.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Oystermouth Castle'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.
Oystermouth Castle stands on Dinantian Rocks (Undifferentiated), bedrock that formed in the Mississippian. The rock here is limestone with subordinate sandstone and argillaceous rocks.