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.