The placename derives from the Irish Cill Mochóg, meaning the church of Mochóg, a dedication that points toward one of the numerous local saints who established small monastic communities across this region in the early medieval period. A church associated with such a foundation would typically have served as the focal point of the parish for centuries, gathering layers of use, rebuilding, and abandonment as circumstances changed around it.

The pattern is familiar throughout rural Ireland: an early ecclesiastical site, possibly pre-Norman in origin, later absorbed into the medieval parish system and modified accordingly. Churches of this type often feature thick rubble-stone walls, a simple rectangular nave, and occasionally a chancel added during the twelfth or thirteenth century as reform movements reshaped the Irish church. Graveyards attached to such sites frequently continued in use long after the roofless shell of the building was left open to the sky, meaning that the ground around a ruined church can hold centuries of local history in a relatively small area. Whether any such structural or burial evidence survives prominently at the Kilmacow site is not currently documented in available public records.