That judgement, it turns out, was premature. At the centre of the square-shaped graveyard at Killeentierna, the ruins of what may be the original medieval church, or a building closely associated with it, still stand in reasonably stable condition, retaining much of their basic form. Fragments of dressed stone scattered across the graveyard suggest that the structure's influence spread further than its footprint.

The place takes its name from the Irish Cillín Tiarna, meaning the little church of St Tiernach, and it sits within the parish of Killeentierna in the diocese of Ardfert, in the barony of Trughanacmy. The Church of Ireland church built over the medieval site occupies the northern quadrant of the enclosure, and the older ruins lie to its south, a relationship that was already visible on the six-inch Ordnance Survey map of 1841. A survey carried out in 2011 found the graveyard to contain seven named tombs, all but one built to the same design: rectangular limestone structures capped with a hipped roof and a tooled limestone capstone. The oldest of these, Grave No. 14, belongs to the Harold family and is dated 1826. Among the headstones, the earliest inscription dates to 1759 and commemorates a Jn O'Sullivan. Alongside the formal monuments, thirty-seven simple uninscribed stones mark further graves, and at least two of these, Grave No. 149 and Grave No. 150, appear to be reused architectural fragments, pieces of the church itself pressed into service as grave markers.

The graveyard is entered from a car park to the east. Two entrances sit close together at the northeast corner: one through rendered square piers hung with wrought-iron gates, the other a traditional stone stile consisting of a V-shaped gap in the wall with a single flagstone as a step. In the northwest corner, a more recent grotto has been constructed, incorporating further architectural fragments from the medieval fabric. A Chapel of Ease occupies a break in the northern boundary wall. The layering is quietly legible once you know what to look for: medieval stonework reused in a grotto, a Protestant church built over a medieval cillín, and an Ordnance Survey man who concluded there was nothing ancient here at all.