The southern and western walls are measurably older than the northern and eastern ones, and the northern wall was never properly keyed in at either end, meaning it was added rather than integrated. Projecting foundations on the outside hint at something earlier still. The windows in the southern wall retain their widely splayed openings with pointed masonry arches, while a blocked door near the western end of the same wall and a broad gap in the west wall, likely the position of a former doorway with an attic window above, record uses and alterations that were never fully erased.

The church served as the parish church of Mogeely and was recorded as being in repair in 1615, 1694, and 1774, which suggests a long and moderately well-maintained life before it was eventually superseded. A new Church of Ireland building was raised at Curraglass in 1778, and the Mogeely church fell out of use; even that replacement has since reduced to foundations in an overgrown churchyard. The most arresting element of the surviving ruins is the roughly square annexe attached to the eastern end of the northern wall. Probably a vestry originally, it was later converted into a private burial enclosure for the Croker family and is entered through an iron gate in its western wall. Inside, two limestone plaques are mounted on the northern wall. The upper one bears a skull and crossbones beneath the words "Memento Mori"; directly below it is a Latin inscription commemorating the Coppinger family. To the west of these sits a rectangular stone with an armorial plaque and an inscription to Walter Croker, dated 1700. The layering of families, memorials, and architectural phases within a single small annexe gives the whole structure an unusually compressed sense of elapsed time.