Where the promontory narrows to a neck of around 200 metres, five earthen banks were thrown up one behind the other, each separated by a fosse, the term for the ditch cut to make each bank both deeper and more forbidding. Two of those banks are substantial earthworks, the inner one still standing to an internal height of 1.6 metres; the others are lower, though the outermost pair extend only along the southern approach as far as the entrance, suggesting the builders gave careful thought to where an attacker was most likely to come from. The entrance itself is just three metres wide and crossed by causeways, the kind of bottleneck that would slow any approach to a crawl.

A promontory fort uses the sea as its primary defence, with artificial earthworks closing off only the landward side, and this example is one of the more elaborate surviving examples of the type in West Cork. The promontory it occupies is a considerable piece of ground, roughly two kilometres from northeast to southwest and 550 metres across, tapering as it runs out towards Crow Head. The second bank is stone-faced on its outer side, a detail that suggests not only a concern with structural durability but perhaps also the presence of builders with access to decent masonry skills. The interior is undulating moorland with occasional rock outcrops, and on the northern side there are disused field boundaries and an unusual scatter of stones whose purpose is not immediately obvious. Turf was still being cut here within living memory, which means the land has been in continuous low-level use long after whatever defensive purpose the banks once served had been forgotten.