Dinas Dinlle

Dinas Dinlle is an Iron Age coastal hillfort approximately 2,500 years old, situated on a glacial drift cliff above Caernarfon Bay in Gwynedd, northwest Wales. The fort features a double semi-circular rampart, with 30% of the site already lost to coastal erosion since 1900. Excavations in 2019 and 2022 revealed a 13-metre-diameter stone-built roundhouse with walls over 2 metres thick and slate-paved doorways -- one of the largest ever found in Wales. Roman coins, an intaglio gemstone, quernstones, and Samian ware pottery indicate occupation into the Roman period, possibly linked to trade with the nearby fort at Segontium (Caernarfon). A prominent stone mound may represent a Roman pharos (lighthouse).