These are bullaun stones, a type of prehistoric or early medieval rock feature found across Ireland, characterised by one or more cup-shaped depressions, called basins, ground into the stone. Their precise purpose remains debated; theories range from grain-grinding and pigment preparation to ritual use at early Christian sites. Whatever their original function, they tend to accumulate folklore over the centuries, often becoming associated with cursing, healing, or the granting of wishes.

The larger of the two stones at Kilbeg is a substantial flat-topped earthfast boulder, meaning it is set firmly into the ground rather than resting loose on the surface, measuring roughly 2.55 metres long, 1.30 metres wide, and 0.47 metres in thickness. What makes it particularly notable is the number of basins cut into its upper face: six, which is an unusually high count for a single stone. The smaller companion stone, situated about 19 metres to the north-east and considerably more modest in size at approximately 0.8 metres by 0.75 metres, carries a single basin. The two stones sit on a slope that faces gently to the north-north-west, above a steeper drop towards the valley to the north-west, giving the site a quiet, slightly elevated character within the wider landscape.