It is a small, quietly telling detail: somewhere between the church falling out of use and its walls being patched or robbed, somebody reached for whatever was to hand. The church was already a ruin by 1615, so there was ample time for that kind of improvisation.

The building itself was the former parish church of Grenagh, and what remains gives a reasonable sense of its late-medieval character. The interior measured roughly 22.5 metres east to west and just over 6.5 metres across, making it a substantial structure. Today the east gable stands, ivy-clad, with a window that retains its double ogee-headed light, a form of decorative arch with a gentle S-curved profile associated with late-medieval ecclesiastical stonework in Ireland. The sunken spandrels, the recessed triangular spaces flanking the arch, are still visible, though the central mullion dividing the window is gone. The east end of the south wall survives to a length of about 13.5 metres, and includes a wall press, a small built-in recess used for storing liturgical vessels or books. Further along the same wall, a wide opening of over three metres shows signs of more recent repair. The north wall has been reduced almost entirely to foundations beneath the sod. Scattered around the graveyard that now occupies the northern half of the site are additional fragments: a cut-limestone arch stone with a chamfered edge from a door surround, and the head of a single ogee light with sunken spandrels, both lying loose among the graves.