The name Killaan itself offers a small clue to its origins. The "Kill" prefix derives from the Irish "cill", meaning a church or monastic cell, a word that appears across hundreds of Irish placenames and almost always signals an early Christian foundation, often pre-Norman in date. Whatever congregation once gathered here, the site has quietly accumulated centuries of silence.

Beyond the placename, the detailed history of this particular church, its founders, the order or community associated with it, the dates of its construction or abandonment, remains, for now, out of easy reach. Killaan is not unusual in this respect. Galway is dense with early ecclesiastical sites, many of them established between the sixth and twelfth centuries, later absorbed into the parish structures introduced after the Anglo-Norman arrival, and subsequently left to ruin following the upheavals of the Reformation and the Cromwellian period. The shell of a small nave, a tumbled gable, a graveyard that continued in use long after the roof fell in: these are the typical traces such places leave behind.