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Swansea Castle is a medieval fortification occupying a commanding position above the River Tawe in south Wales. The castle sits upon bedrock of the South Wales Upper Coal Measures Formation, a geological sequence of mudstone, siltstone and sandstone deposited during the Westphalian period, interspersed with coal and ironstone seams that would eventually form the basis of the region's industrial economy. This solid foundation of resistant strata provided a stable platform for the castle's construction.
The monument was established as part of the Norman penetration into South Wales during the twelfth century, controlling a strategic site at the head of the Tawe valley. Its location reflects medieval priorities of territorial command and access to water transport. The site's geological substrate, whilst suitable for building, presented challenges typical of upland Welsh locations, where water drainage and exposure to prevailing winds required careful consideration in the castle's planning.
Swansea Castle is protected by Cadw, the Welsh Historic Monuments service, under reference GM441. The castle remains an important testimony to Norman military and administrative organisation in medieval Wales, its position relative to the surrounding landscape and underlying geology demonstrating how medieval builders exploited both topography and geology to establish defensible strongholds in conquered territories.
Original Swansea Castle is a scheduled monument protected by Cadw under reference GM441. View the official record →
Swansea Castle is a medieval fortification occupying a commanding position above the River Tawe in south Wales. It is designated a Scheduled Ancient Monument by Cadw under reference GM441.
Original Swansea 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.
Original Swansea 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 GM441.
Several scheduled monuments lie within 10 km, including Swansea Castle (0.1 km), Foxhole River Staithes (1.2 km), White Rock Copper Works (1.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Original Swansea 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.
Original Swansea Castle stands on South Wales Upper Coal Measures Formation, bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.