Tre'r Ceiri

Tre'r Ceiri ([treːr ˈkɛiri] ⓘ) is a hillfort dating back to the Iron Age.

[1] The settlement is 450 metres (1,480 ft) above sea level on the slopes of Yr Eifl, a mountain on the north coast of the Llŷn Peninsula in Gwynedd, north-western Wales.

Evidence suggests the fort was first built around 200 BC, though most of the archaeological finds date from AD 150–400, showing the site continued as a settlement during the Roman occupation.

The settlement is surrounded by stone walls that are largely intact, and which reach up to 4 metres (13 ft) in some places.

[3] Historian John Davies suggests that because the settlement is so far above sea level, the huts served as habitations for summer shepherds who also had winter dwellings in the lowlands.

View of the fort from Garn Ganol, the upper peak of Yr Eifl
Reconstruction