Banks, ditches, levelled walls; the traces are slight enough that without careful attention you might mistake them for natural coastal erosion or the remnants of agricultural boundaries. What makes this stretch unusual is not one dramatic fortification but the accumulation: six separate promontories, each showing similar evidence of having been deliberately cut off from the land behind them.

A promontory fort is, in its simplest form, a headland made into an enclosure by building a barrier across the narrow neck of land connecting it to the mainland, allowing the sea to defend the remaining sides. They are found all around the Irish coastline and date from a broad span of prehistoric and early historic periods, though many remain unexcavated and undated. At Ard na Caithne, the picture is unusually varied across the six headlands. The two northernmost carry low earthen banks and the remnants of a levelled drystone wall crossing the neck. The broad rectangular headland adjacent to them shows a wide, levelled straight bank and a faint fosse, which is a defensive ditch, across its neck. The southernmost of the six has a slightly curving fosse, now filled in, defending its approach. The middle two are cut off by more recent earthen banks, though vaguer traces suggest that earlier defences also existed there. A survey carried out in 2002 by Casey noted that not enough survives to determine the precise nature of these remains, but concluded that all six headlands are candidates deserving further investigation.

What is quietly compelling about this site is its unresolved quality. The evidence is too consistent across six separate headlands to be coincidental, yet too fragmentary to confirm what was built here, by whom, or when. It sits in that common but underappreciated category of Irish archaeology: places that clearly meant something, but have not yet given up what.