This subcircular enclosure measures 15.2 metres internally from north to south and 16.9 metres from east to west, surrounded by a substantial collapsed stone wall that was originally about 2.2 metres wide and reached heights of up to 56 centimetres. Despite centuries of weathering, sections of the wall retain their inner and outer facing stones, with some areas preserving up to three courses of the original construction.

The most intriguing feature of this site lies hidden in the southeast sector, where a largely filled souterrain extends beneath the ground. This underground passage, oriented from east-northeast to west-southwest, reveals itself as a 5.1 metre long depression on the surface, widening from 85 centimetres to 2 metres at its western end. A single roof slab remains visible in the depression, offering a glimpse into the 1.1 metre wide chamber below. The eastern end of this subterranean structure may have originally extended beneath the cashel wall itself, suggesting a sophisticated defensive design typical of early medieval Irish fortifications.

An additional defensive element encircles the main cashel wall at a distance of 21 metres on the northern side, where a discontinuous wall or stone setting sits 6 to 7 metres below the level of the primary fortification. This outer boundary, combined with the site’s elevated position amongst rock outcrops, would have provided the inhabitants with both excellent visibility of approaching visitors and multiple layers of defence; a testament to the strategic importance of this location in medieval Donegal.