The place is called Eochair Na Gcailleach, and what survives there is a promontory fort, a type of enclosure in which a natural coastal feature does most of the defensive work. Rather than building walls on all sides, the people who made this place relied on the cliffs themselves to secure three flanks, cutting off the landward neck of the headland with a single earthen bank and ditch.

The headland itself is roughly rectangular, measuring 89 metres east to west and 49 metres north to south. The bank defending its neck is 4 metres wide and 0.7 metres high, which is modest enough in isolation, but its outer face retains clear traces of a sandstone slab revetment, meaning the earthen bank was faced with upright or carefully laid stone to hold its shape and present a harder edge to any approach. The ditch in front of it is considerably harder to read today; a path has been worn through it over the years, and a more recent field bank has been thrown up along its outer edge, obscuring any evidence of a counterscarp bank, the secondary ridge that sometimes ran parallel to a ditch to slow an attacker further. No original entrance has been identified. The interior slopes steeply downward to the north, and only the northeastern corner of the enclosed area, known as the garth, would have offered any practical space for settlement or shelter. A freshwater stream runs over the cliff edge near the site, which would have made the place at least marginally viable for occupation. The landscape surrounding it is characteristic of this stretch of Mayo: exposed bogland, shallow soil over outcropping rock, and higher ground rising to the east and north that would have left the fort visible, and overlooked, from the landward side.