This is a rath, the most common type of early medieval settlement monument in Ireland, a roughly circular enclosure formed by one or more earthen banks and ditches within which a farming family would have lived, kept animals, and stored goods. What makes the example at Ballinvoher worth a closer look is the detail that survives in its fabric: this is not a vague lump in a field, but a monument whose original engineering is still largely readable at ground level.

The enclosure measures roughly 38 metres north to south and 36 metres east to west, making it a modestly sized but well-preserved example of its type. The earthen bank rises to about 0.95 metres on its interior face and a more substantial 2.5 metres on the exterior, giving it a genuinely defensive profile. Outside the bank runs a fosse, a ditch, though it is now relatively shallow at around 0.25 metres deep. The entrance, 6 metres wide, faces east, and three stones on its northern side form a low revetment, the kind of structural edging used to stabilise a gap through the bank. Some stone facing survives on the outer bank just north of this entrance. Perhaps most intriguing is the interior itself: the northern edge has been raised slightly by about half a metre, which both levelled the sloping ground inside and created a secondary inner fosse. This kind of internal earthwork suggests careful management of the site's topography. On the Ordnance Survey six-inch map of 1842, a small circular feature was marked within the interior, though what it represented is no longer clear on the ground.