The enclosure measures 29 metres across in both directions, its earthen bank still standing up to 1.55 metres at its highest point. Two gaps interrupt the circuit, one to the east at three metres wide and one to the south-west at three and a half metres, almost certainly the original entrance points used by whoever lived within. On the southern side, the interior has been deliberately built up to level out the natural fall of the hillside, a small but telling piece of engineering that speaks to the care taken in constructing what was once somebody's home.

This is a rath, the most common type of early medieval settlement in Ireland. A rath is essentially a farmstead enclosed by one or more earthen banks and ditches, typically housing a single family and their animals, dating broadly from the sixth to the twelfth centuries. Tens of thousands once existed across the island, though many have been lost to agriculture and development. What makes the Killeagh example particularly interesting is the presence of a souterrain on its eastern side. A souterrain is an underground stone-lined passage or chamber, often interpreted as a place of refuge, cool storage for dairy produce, or both. They are frequently found in association with raths, but their survival alongside the surface monument intact enough to record is always notable. The combination of the levelled interior, the two opposing entrance gaps, and the underground annex gives a clearer-than-usual sense of how such a place was actually organised and used.