A rath, to give it its proper term, is a roughly circular enclosure defined by an earthen bank and an accompanying ditch, or fosse, and was typically the farmstead of an early medieval family of some standing. At Cill Mhic An Domhnaigh, the proportions are considerable: the interior measures roughly 30 by 34 metres, the fosse drops as far as 3.2 metres below the surrounding ground level, and the bank rises more than 4 metres above the base of that ditch. The causewayed entrance, facing due east, is three metres wide, and the whole structure sits on a gentle east-facing slope with open sightlines in every direction.

What makes this particular rath quietly unusual is the density of domestic detail preserved inside. Three stone-walled huts are arranged within the enclosure, connected to one another by short passages and linked to the entrance by a paved path, none of which are now visible at surface level. The easternmost hut is roughly 7.6 metres across internally; the middle one about 5 metres; the westernmost just 3.4 metres, entered by a passage from the south-east. A mound in the southern part of the interior may indicate a fourth. There is also a souterrain, an underground stone-lined passage typically used for storage or concealment, which opens off the north-western side of the smallest hut and probably ran all the way through the bank to a second exit on the south-western face. In 1968 the Office of Public Works produced a sketch plan of it, but the outer opening lies in dense overgrowth and has never been precisely located. That same investigation dug a trench through the interior to trace the hut outlines, heaping the spoil to either side in a way that disturbed much of what it sought to document. The surviving wall height in the huts is now no more than 0.2 metres. J. Cuppage documented the site in the 1986 Dingle Peninsula archaeological survey, and it has been under a preservation order since 1958.