What remains of the structure at the centre of the Kilnahue graveyard measures roughly twenty metres by six and a half, oriented east to west in the manner of Christian churches across Ireland, but its stonework carries no readable architectural features: no window jambs, no decorative carving, no distinguishing mouldings. It is, in the plainest sense, a ruin that has forgotten what it looked like.

The graveyard itself is oval in plan, approximately fifty metres across its east-west axis and forty-four from north to south, bounded by a stone-revetted earthen bank. That oval shape is worth pausing over. Early medieval ecclesiastical enclosures in Ireland were frequently laid out in this form, suggesting that Kilnahue may have roots considerably older than whatever building now lies overgrown at its centre. Lying loose just to the north of the church is a cross-base, an irregularly shaped, flat-topped stone with a rectangular mortice cut into its upper surface. A mortice is simply a socket, in this case intended to receive the upright shaft of a now-missing stone cross. The base measures roughly eighty centimetres by forty, and stands about forty centimetres high. Without its cross it reads as an orphaned piece of furniture, functional in design but stripped of its purpose. Further context comes from the surrounding landscape: a souterrain, which is an underground stone-lined passage typically associated with early medieval settlement and used for storage or refuge, lies about twenty-five metres north of the church, just outside the graveyard boundary. An enclosure of some kind sits roughly a hundred metres to the west. Taken together, these features point to a site that was not simply a place of worship but part of a wider cluster of early activity settled into this sheltered, north-facing valley.