🇮🇪 Ireland · Earthwork
Grianan of Aileach
Iron Age to Early Medieval (c.1000 BCE–1100 CE) · Iron Age Gaelic → Early Medieval Uí Néill
Donegal hilltop royal cashel (23.5 m diameter) on Greenan Mountain — northern Uí Néill kingship inauguration fort.
🇮🇪 Ireland · Earthwork
Dún Aonghasa
Late Bronze Age to Early Medieval (c.1100 BCE–800 CE) · Atlantic Iron Age / Early Medieval Gaelic
Cliff-edge triple stone fort on Inishmore (6 ha) with massive chevaux-de-frise of jagged limestone — Ireland's most dramatic hillfort.