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Sully Island, "Danish" Fort is a prehistoric hillfort located on an island off the coast of the Vale of Glamorgan in South Wales. The site comprises defensive earthworks including a substantial rampart and ditch system that enclose an area on the island's summit, characteristic of Iron Age fortified settlements in South Wales. Despite its popular designation as the "Danish" Fort, there is no archaeological or historical evidence supporting Viking occupation, and the fortification is understood to date to the Iron Age period. The site remains significant as an example of coastal defence strategy in prehistoric Wales, with its island location providing natural defensive advantages supplemented by constructed earthworks.
Sully Island, "Danish" Fort is a scheduled monument protected by Cadw under reference GM035. View the official record →
Sully Island, "Danish" Fort is a prehistoric hillfort located on an island off the coast of the Vale of Glamorgan in South Wales. It is designated a Scheduled Ancient Monument by Cadw under reference GM035.
Sully Island, "Danish" Fort dates from the prehistoric period, and is classified as a hillfort. It is one of over 32,000 scheduled monuments protected across the UK.
Sully Island, "Danish" Fort 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 GM035.
Several scheduled monuments lie within 10 km, including St Mary's Well Bay Pillbox (0.8 km), Anti-aircraft and Coastal Battery West of Lavernock Point (1.2 km), Middleton Moated Site (2.5 km).
Aubrey generates in-depth historical research for any address in the UK — drawing on scheduled monument data, Domesday records, Roman heritage, PAS finds and medieval history to reveal the complete story of a landscape.
Research the area around Sully Island, "Danish" Fort