Not soldiers or ceremonial occupants in any grand sense, but inhabitants of a small circular house, its foundations dug into the accumulated debris of an even older past.

The house, the best preserved of four similar structures uncovered in the same excavation cutting, was scooped out as a circular hollow and then lined with upright stones set at varying depths to create an even-topped wall, a method used consistently across all four structures. The internal diameter measured 4.85 metres. Remarkably, the foundations of the enclosure's inner terrace were found resting almost directly on top of the house wall, meaning the great defensive architecture of Dún Aonghasa was built right up against, and partly over, these domestic structures. The house had been dug into a layer of decomposed Late Bronze Age refuse and windblown soil, so its occupants were already living above centuries of earlier human activity. Surviving segments of limestone revetment walling, a threshold stone marking an eastward-facing doorway roughly 85 centimetres wide, and a hearth in the south-west quadrant with a flat slab base all speak to a modest but carefully constructed dwelling. A spudstone, a small upright stone set beside a doorway to prevent the door from swinging too far, survived on the south side of the entrance. The floor retained scattered limestone paving and, dispersed across the interior, animal bones and spreads of limpet shells. The finds were a mixture of periods: Late Bronze Age pottery, crucible fragments, a bone spindle-whorl, a blue glass bead, part of an amber bead, scraps of iron, and a small lug-handled crucible. Only one object could be firmly tied to the period of occupation: a finely made segmented-headed bone pin, found embedded in the paving of the south-east quadrant. On the basis of that single pin, the house is dated to the early medieval period, somewhere in the broad span roughly between the fifth and twelfth centuries, a time when Dún Aonghasa appears to have functioned not merely as a monument but as a place where people cooked, ate shellfish, and fastened their clothing with carefully crafted bone.