The Down Survey, a vast mapping project carried out in Ireland in the 1650s to facilitate the redistribution of land after the Cromwellian conquest, recorded the church on its map of Killagh parish with the annotation 'in repaire', while a written terrier accompanying the same map listed 'a Ruined Church' among the features of the townland. The castle nearby, by contrast, was noted as still serviceable. That distinction, ruin against working structure, tells you something about how quickly a church could fall out of use once the conditions sustaining it changed.

The church had stood on lands belonging to George Nugent, described in 1641 as an 'Irish papist', a designation that under the political circumstances of the time carried significant consequences for land ownership. The building itself was a rectangular structure, roughly 6.3 metres north to south and nearly 20 metres east to west, aligned on a slight northwest to southeast axis and forming the northern boundary of a graveyard. Its walls were built of limestone rubble. Very little stands to any height today; only a fragment of the western end of the south wall and part of the east wall remain upright, with the lower courses of the rest just barely visible above ground. In the east wall, the inner facing of a window embrasure survives, and a later internal wall, visible on nineteenth-century mapping, once divided the eastern end of the building from the western. Eighteenth and nineteenth-century memorials still occupy the interior.

The ruins sit in open grassland, with a stream running roughly 90 metres to the north and, crowding in from other directions, the remains of a motte and bailey castle just 60 metres to the south and Killagh House and castle 150 metres to the west. A motte and bailey is a Norman-period fortification type, consisting of a raised earthen mound topped by a timber or stone structure, set beside an enclosed courtyard. Aerial photography has also revealed curvilinear earthworks encircling the church and graveyard on three sides, some of which may date to the church's active period, while others are thought to relate to later drainage works. The cluster of features in this small area, mill, castle, church, earthworks, graveyard, gives the landscape an unusually layered quality that the ruins themselves, modest as they now appear, only hint at.