Here, three sides of the roughly triangular platform, measuring approximately 33.5 metres by 23 metres at its widest, drop away in high, steep cliffs facing north. The defensive effort was concentrated on the northeast, where the land connects the promontory to the mainland, and it is there that the surviving archaeology is most legible.

The landward side is defended by a low bank of earth and stone, about three metres wide and still standing some 0.3 metres high, fronted by an external fosse, or ditch, of similar width and cut to a depth of around half a metre. Beyond that ditch, at its outer lip, a second bank rises slightly higher, to 0.5 metres. This double-barrier arrangement, bank and ditch and outer bank, is a classic configuration for Irish promontory forts, providing a modest but meaningful obstacle to anyone approaching across open ground. A modern stone wall now cuts across the interior, separating the enclosed area from the earthwork defences, which complicates the reading of the site at a glance. Curiously, when the Ordnance Survey mapped this stretch of coastline for their six-inch series in 1837, the fort was not marked as an antiquity at all, suggesting it was either overlooked or not yet formally recognised as such. The OS Letters of the same year, however, do record that local tradition knew the place as Dún Balra, preserving a name, dún being an Irish word for a fort or defended enclosure, that almost certainly pre-dates the cartographers by many centuries.