The building is attributed to St Columbkille, better known as St Columba, who is said to have founded it after being expelled from Aran. According to one account, Columba had crossed to the islands to study at St Enda's celebrated monastic school, arriving, in the phrase preserved by later writers, 'with scholars-belt and book-satchel, to learn divine wisdom.' On his return journey he came ashore at a rock directly below the church site, a rock still known locally as the Saint's Rock. The antiquary Thomas Johnson Westropp, writing around 1900, dated the structure tentatively to the tenth century, though the saint himself lived in the sixth, which suggests either a later foundation in his memory or the usual difficulty of pinning early Irish ecclesiastical buildings to a precise moment.

When John O'Donovan visited in 1839, he found the church already 'much injured by the tooth of time,' with the west gable wall level with the ground. What survives today is an ivy-clad rectangular structure aligned east to west, built largely from undressed, roughly coursed stone, with some notably large blocks, a technique sometimes described as cyclopean masonry for the sheer scale of the individual stones used. The east gable is the most complete section and contains a narrow round-headed window set within a splayed internal embrasure. The south wall preserves a second window, its head formed from a single well-dressed stone with similarly finished jambs, though several stones have been robbed out over the centuries and others plastered over. A severe structural crack runs through that embrasure. The north wall survives only in a short section near the east corner, and a modern wall has been built along part of its course. To the east of the ruins, a scatter of rubble includes at least one dressed arch stone, possibly from the original doorway. Roughly thirty metres to the west lies a souterrain, an underground stone-lined passage of the kind associated with early medieval settlement, suggesting the church did not stand in isolation.