The walls stand to their original height, the gables reaching 4.4 metres on the interior, and the pointed-arch doorway in the south wall still retains its hanging-eye, the iron pivot socket into which a door hinge would once have been set. That a functional detail like this survives four centuries of neglect says something about the quality of the original construction, a rectangular nave of undressed but carefully coursed limestone blocks packed around a mortared rubble core.

The church sits about 300 metres south of the foreshore at Gleninagh, within a graveyard that is itself set in the south-west corner of a poorly preserved ecclesiastical enclosure, the kind of circular or sub-circular boundary that in Ireland often marks an early medieval monastic or church site. By 1302, a church at a place recorded as 'Glaniednagh' appears in Papal tax records, meaning the settlement was sufficiently established to be contributing to the Church's administrative finances. By 1615, a survey found it already 'ruyned'. Whatever happened in the intervening three centuries is not documented. The fabric that survives suggests a medieval building of some ambition: the west gable has well-dressed corner quoins and a small projecting plinth of two courses of thin flags at its base, while the east gable, though its quoins are rougher, contains a narrow round-headed window, 1.37 metres tall but only 12 centimetres wide, set in a carefully formed round-arched embrasure. The asymmetry between the two gables, one more finished than the other, hints at building in phases or to different budgets.

A fragment of dressed stone lying loose near the west end of the interior may once have been part of a font. If that identification is correct, it is a small but telling reminder that this was a place of active parish life before it fell silent.