It is a small, practical detail, but it speaks to a level of deliberate craft that runs through the whole building. This is the only medieval church still standing in its parish, and it rewards close attention.

When the Ordnance Survey recorded it in 1840, the walls were already ruinous, standing roughly three metres high around a footprint of about eighteen by six metres. By 1907, when antiquarian S.J. Seymour examined it more carefully, the building was considered to be in good preservation for its age. His account noted the pointed south doorway, the twin-light ogee-headed east window, still with its mullion in place, and a piscina set into the south wall near the east end. A piscina is a shallow stone basin used for rinsing sacred vessels, a standard feature of medieval liturgical practice. The present fabric confirms all of this and adds further detail: ivy-leaf carvings decorate the spandrel of the east window and the chamfer stops of the limestone doorway, glazing grooves survive on the window jambs, and cross-marks incised into the dressed stone of the doorway jambs may be original masons' marks. Beam holes cut into the north and south walls at the western end suggest a wooden floor at that level, possibly a gallery or a two-storey priest's residence. Traces of internal render survive on the north wall, and the underside of the door arch preserves evidence of wicker centring, the curved temporary framework used to support an arch during construction, a detail rarely visible once a building is complete.

The church sits in the north part of the Annagh townland, to the north of the road running through it, surrounded by a small graveyard whose oldest legible tomb is dated 1781. The walls, built in random rubble with alternating long and short dressed quoins and a slight base batter at both gables, stand to a reasonable height. The north wall has no windows, which makes the interior feel distinctly asymmetric from outside; the light all comes from the south and east. The west gable carries a flat-headed window set high up, which was already choked with ivy when Seymour visited.