Dinas Dinlle

Dinas Dinlle is a hillfort in Gwynedd, north-west Wales.

The cliff above the beach is known as Boncan Dinas and is occupied by an Iron Age hillfort, Dinas Dinlle itself. This fort has been eroded by the sea, such that only a double semi-circular rampart remains. Finds of Roman pottery suggest reoccupation in the 2nd or 3rd centuries CE. The fort is now (after centuries of erosion from the west) about 150 metres from north to south, 110 metres east to west, with an entrance on the south west.

Archaeological excavations at Dinas Dinlle in 2019 and 2022 found the remains of structures inside the hillfort. These included a stone-built roundhouse, 13 metres in diameter, with walls more than 2 metres thick, and threshold slabs of quarried slate. It is thought to be the largest roundhouse in Wales. The excavations also found Roman coins and pottery dating from around 200CE to 300CE. The survey with ground-penetrating radar found several round houses and yards connected to the entrance by cobbled roadways. The archaeological work was undertaken by the Gwynedd Archaeological Trust and the RCAHMW with funding from the EU 'CHERISH' project.