The interior of this ancient coastal fort measures only about 18.8 metres east to west and 23.5 metres north to south, yet the wall defending its landward side ranges from 2.2 to 4.37 metres in thickness, and in places still stands over four metres above the interior floor. On the north and south sides, sheer cliffs dropping roughly 13 metres to the sea do the work that stone would otherwise have to. A promontory fort is exactly what the name suggests: a headland or coastal spur turned into a fortified enclosure, typically by blocking the one approach that cannot be defended by the sea itself. What makes this one quietly peculiar is that the interior was once farmed. The Ordnance Survey Name Books for Cloghane record that the ground inside was formerly cultivated, and a single course of walling extending five metres along the southern edge of the promontory may be a remnant of some kind of perimeter boundary from that agricultural phase.

The site is known locally as An Cathairin, a diminutive form of the Irish word for a stone fort, and the surrounding landscape holds further traces of its long presence in local memory. The writer and Irish-language scholar known as An Seabhac, writing in 1939, recorded two nearby placenames: Log an Dúinín, meaning roughly the hollow of the little fort, and Cuas na Cathrach, the cove of the fort or city. These names suggest the site was well-embedded in the area's oral geography long before archaeologists turned their attention to it. The outer face of the wall has been absorbed into the modern field boundary system and may have been substantially rebuilt at some point, which complicates any reading of the original structure. Two terraces can be traced along short stretches of the inner north face, hinting at a more complex original construction, though no entrance gap survives in the present remains. The detailed survey of the site was carried out by J. Cuppage as part of the Corca Dhuibhne archaeological survey of the Dingle Peninsula, published in 1986.