The one on the eastern slope of a ridge at Burriscarra, in County Mayo, is something more elaborate: a trivallate ringfort, meaning it was originally ringed by three concentric banks and ditches. That triple-layered architecture signals a site of some significance, whether as the home of a person of higher social standing or as an enclosure requiring unusually robust protection.

The fort measures roughly 61 metres north to south and 60 metres east to west, making it a substantial enclosure. A wide fosse, the term for the defensive ditch dug to create the bank material, still separates the inner and middle circuits. The innermost bank, now only about 0.3 metres high, survives intact, while the middle bank reaches 1.5 metres in places, though it has been levelled along its northern arc. The outer bank has fared worst, flattened across much of its western and northern stretches. A formal entrance, just over five metres wide and fitted with a causeway crossing the ditches, cuts through all three banks on the south-eastern side, the most common orientation for ringfort entrances in Ireland. The whole site sits in pasture and is heavily overgrown, which simultaneously obscures its plan and, in its own way, preserves what survives beneath the vegetation.