This is a bullaun stone, a type of ancient carved or naturally hollowed rock found across Ireland, typically associated with early Christian or pre-Christian ritual activity. The circular depressions, called bullauns, were once thought to have been used for grinding grain, though the more widely accepted view is that they held votive or curative significance, with the water that collected in them believed to have healing properties. They are often found near ecclesiastical sites, holy wells, or old burial grounds, which makes the geography around Mortlestown particularly worth noting.

The site sits in quiet relationship with its surroundings. A holy well, recorded separately in the national monuments register, lies approximately 270 metres to the east, a proximity that fits the pattern seen elsewhere in Ireland where bullaun stones and holy wells cluster within the same sacred landscape. The stone does not appear on the 1840 edition of the Ordnance Survey Ireland six-inch map, which suggests it was either overlooked by the original surveyors or not considered significant enough to mark at the time. It does appear, annotated simply as "Stone", on the later Cassini edition of the same map series, which indicates it had come to someone's attention by the time that revision was made. The record was compiled by Fiona Rooney and uploaded to the national monument database in November 2021, with the monument also confirmed through Digital Globe and Google Earth orthoimages taken between 2011 and 2013.

The stone sits in agricultural land, so access would require local enquiry before approaching across any field boundaries. The holy well to the east is recorded separately and may offer a more accessible starting point for anyone trying to orientate themselves in the area. The bullaun itself is subtle on the ground, the kind of thing that rewards careful looking rather than announcing itself. Satellite imagery confirms it is still present and visible in the pasture, though the detail of the hollow is best appreciated close up and in low, raking light.