That quiet architectural deception is easy to miss when you first encounter the place, a roofless but largely intact medieval structure sitting at the centre of a working graveyard at Ballynakill, its limestone walls still standing to their full height and partly smothered in ivy.

The building is what survives of the parish church of Kilfinny, and its fabric tells a layered story. The nave and chancel are not contemporary: the side walls of the nave butt up against the east end wall in a way that indicates the chancel was added later. A record from 1615 notes the church was still in repair at that date, suggesting it remained in active use well into the post-Reformation period. By 1718, however, the Pigott family had already claimed a foothold here; a defaced limestone memorial on the south wall of the chancel was erected that year by one John Pigot in memory of his family, as noted by Fitzgerald and McGregor in 1826. The connection deepened in 1810, when the chancel was formally converted into a private burial enclosure for the Pigotts, at which point the wall between nave and chancel and the chancel arch were heavily rebuilt. The antiquarian Thomas Westropp, writing in 1904 to 1905, recorded both the conversion and earlier details of the structure. Some original fabric does survive: the inside edge of the chancel's east window embrasure retains its semi-circular arch, as does the south chancel window, whose single arched light is chamfered on the outer edge.

The entrance is through a doorway near the west end of the south wall of the nave. The west side of the door surround has been lost, but the east side preserves plain limestone jambs, the uppermost of which projects outward to carry a large lintel; that lintel has cracked recently and bears a shallow rectangular raised panel on its front face. Inside the nave, the floor is almost entirely given over to burials, the earliest headstone dating to the mid-nineteenth century. High on the north wall, a blocked opening, known in Irish architectural recording as an ope, is visible but gives nothing away about its original purpose. A damaged window near the east end of the south wall once lit the nave; only the basic form of its segmental-headed light can be made out now. The graveyard remains in use, so the site is generally accessible, and the walls are substantial enough that the building reads clearly even from the perimeter.