That corner, the south-east angle of a tapered rectangular block, is where the ogham runs: ogham being the early medieval Irish writing system in which letters are encoded as groups of notched or scored lines cut along the edge of a stone. The scores here are large, broad, and regularly spaced, legible between roughly 0.65 and 1.5 metres above the ground, though the surface has been damaged in sections by flaking and abrasion, and a shallow depression worn into the earth encircles the base where generations of animals have gathered. The uppermost portion of the angle is rougher, lichen-covered, and ambiguous; it is not clear whether it was ever inscribed at all.

The inscription was read by the scholar R.A.S. Macalister in 1945 as QASIGN[I] MAQ[I], a partial formula of the kind common to early Irish ogham stones, where MAQ[I] is the genitive of the word for son, typically used to record a person's patronymic. The stone's history took a more recent turn in 1861, when it was re-erected after having fallen and lain on the ground for an unknown period. A published account from 1900, referring to it as the Tullaghane ogham stone, noted that a large chip had been knocked from the inscribed angle near the bottom, presumably during or before this episode. The stone sits close to the Mayo and Roscommon border, which follows a roughly north-east to south-west path through the surrounding landscape, and its position on a broad terrace on the slope of a ridge places it in quiet conversation with the wider countryside. To the south-south-west, across a broad valley of rolling grassland, Kiltullagh Hill rises on the far side, and on its summit a standing stone is visible; to the east of that, the outline of a church. Both the ogham stone and the hilltop standing stone sit near this same county boundary, lending a faint sense of alignment, or at least of ancient attention paid to this particular stretch of ground.