At the base of the shaft, the lines turn outward at right angles and run all the way to the edges of the stone, as though the cross is bracing itself against the slab's own boundaries. It is a small formal detail, but one that gives the carving an almost architectural quality, distinct from the more fluid knotwork or ringed crosses found elsewhere in the early medieval repertoire.

The slab sits in the eastern half of what is known as the Saint's graveyard on the island, a burial ground associated with the monastic settlement that made Inis Cealtra one of the more significant ecclesiastical sites in the west of Ireland. The stone measures roughly 1.65 metres by 0.5 metres, and the cross is carved with hollowed angles, meaning the spaces where the arms meet the shaft are scooped or concave rather than squared off cleanly. The antiquarian R. A. S. Macalister examined it in the early twentieth century and placed it as twelfth-century in type, which would locate it in a period when Irish monasticism was undergoing considerable reform and outside Romanesque influences were beginning to reshape both architecture and decorative stonework. A cross-slab, in general terms, is a flat upright stone bearing a carved cross, used as a grave marker or devotional monument, and they survive in considerable numbers at Irish ecclesiastical sites, though few have quite this particular quirk at the shaft's base.