A bullaun stone is a boulder or outcrop bearing one or more cup-shaped depressions, ground into the rock over centuries, probably for purposes that mixed the practical with the ritual. They are common enough features of early Christian and earlier sites across Ireland, yet they have a habit of disappearing, overgrown by grass, buried under soil, or simply overlooked in the field. The example at Kilrainy in County Kildare is a case in point: recorded in 1985, it sits on a gentle east-facing pasture slope, roughly fifty metres to the north-east of a cluster of early ecclesiastical remains, yet when surveyors returned to the site it could not be found.

The broader setting makes the absence all the more tantalising. The surrounding area preserves traces of what may be an early ecclesiastical enclosure, the kind of roughly circular boundary that often marks the footprint of an early Irish monastic or religious site, along with the remains of a church and a graveyard. The bullaun stone, had it been relocatable, would have fitted neatly into that landscape of long, layered religious use. Its first formal recording dates to 1985, though the stone itself is almost certainly far older than that notation suggests.