It carries an incised double-lined cross with a circular centre and D-shaped or semi-circular terminals, all contained within a rectangular incised frame. The slab measures 1.15 metres long and 0.45 metres wide, substantial enough to have been a deliberate and significant object in its own right. At some point its edge was broken away, taking part of one arm of the cross and a section of the surrounding frame with it. Whoever later repurposed the stone as a lintel in the south wall of the church may have known exactly what they were using, or may simply have needed a piece of the right dimensions.

The church itself stands on ground with wide views to the west, north, and east, within a rectangular graveyard in Co. Westmeath. It occupies the site of the Early Christian monastery of Lecan-Midhe, which appears in the Annals of Ulster under the year 750 with the recorded death of Fursu, abbot of Lecan Midhe. The monastery is attributed by the nineteenth-century scholar John O'Donovan to St. Cruimín, whose principal feast day was celebrated on 28th June. A second feast day for the same saint, sometimes rendered as Croimín, fell on 29th December according to the Martyrology of Tallaght. Cross-slabs, a form of early medieval stone carving common across Ireland, were typically incised rather than fully sculpted, marking graves or significant points within a monastic enclosure. That this one was eventually pressed into structural service says something about how communities across centuries understood, or set aside, the sanctity of older objects when practical needs arose.