The surviving north and south walls, spanning roughly thirty metres in total length and enclosing a rectangle just under eight metres wide, bear the marks of repeated alteration and rebuilding over their lifetime. A segmental arched doorway at the western end of the south wall has lost its surrounds entirely, and the window openings in both walls have shed their dressed stonework, though the ghost of a triple-pointed east window can still be made out, with traces of its hood moulding and the plank-centring once used to form its pointed embrasure. A trefoil-headed piscina, a small stone basin set into a church wall for rinsing communion vessels, was recorded in the south wall's eastern end, though whether it still survives in readable form is uncertain. Six corbels project from the outside of the south wall in two rows, suggesting the church once carried a structural element, perhaps a lean-to or external passage, that has long since gone.

The building was the parish church of Rathbarry, and it was apparently still functioning in 1615, when it was recorded as being in repair. By 1693 it had already fallen into ruin, a trajectory shared by many Church of Ireland parish churches in rural Munster during the upheaval of the late seventeenth century. Inside, headstones crowd the interior, as they do in many ruined churches that became informal graveyards after their roofs failed. The most prominent is the tomb of Ralph Freke, who died in 1717, set against the eastern end of the south wall. The Freke family were the dominant local landowners at Castlefreke, and Ralph's tomb effectively anchors one end of the ruined structure, its placement suggesting the family's long association with this corner of west Cork long after the building around it had ceased to function as a place of worship.