The structure at Killeenavarra sits on the south-eastern edge of a prominent limestone ridge in open pastureland, and while the church itself is large enough, over sixteen metres long on its east-west axis, it is attended by what appears to be a two-storey domestic building and a small annexe of uncertain purpose, the whole complex running to a scale that suggests a more substantial ecclesiastical or institutional presence than the map notation implies.

At least two distinct phases of building are legible in the church walls. The earlier, medieval fabric consists of fairly evenly coursed medium-sized limestone blocks, with a flat-headed window surviving in the north wall and a round-headed doorway that appears to have been reinserted later towards the western end of the same wall. Sometime in the eighteenth or early nineteenth century the building was refurbished, most likely as a mortuary chapel, a private burial structure associated with a family or local gentry. This later intervention involved rebuilding the west gable set slightly inside the line of the original one, so that the north and south walls now project beyond it, the southern extension incorporated into the graveyard boundary wall. A cusped pointed twin-light window was inserted into the east gable during this phase, and a large uninscribed stone vault was constructed to the west of an internal dividing wall, possibly in the nineteenth century. A graveslab nearby carries a date of 1687, suggesting the site had been in use as a burial place well before the formal refurbishment. The domestic building abutting the church to the south-east is constructed of larger, roughly coursed limestone blocks and rises to two storeys. Its upper floor features ogee-headed windows, a decorative form with a characteristic S-curved arch associated with late medieval craftsmanship, and corbels along the south wall indicate that a mural passage once ran across it at first-floor level. A small annexe projects from the south-east corner of this building; its ground floor was apparently accessible only by trapdoor and ladder, a detail that raises questions about storage, security, or both, none of which the surviving fabric answers definitively.