It is one of three ogham stones, ogham being an early medieval script in which letters are represented by groups of notches and lines cut along the edge of a stone, that were found together inside a souterrain at Ahalisky in County Cork. A souterrain is a man-made underground chamber or passage, typically associated with early Irish settlements and used for storage or refuge. The fact that three inscribed stones ended up reused inside such a structure is itself telling: by the time the souterrain was built, the stones had already outlived whatever commemorative or territorial function they originally served.

R. A. S. Macalister catalogued this particular stone in 1945, assigning it the number 71 in his corpus and recording its dimensions as approximately three feet two inches long, one foot wide, and five inches thick. The inscription reads COIMAGNI MAQI MOCOI GA, with the final portion incomplete or lost. Translated loosely from the early Irish formulaic convention common to ogham inscriptions, this would indicate something along the lines of "of Coimagán, son of the tribe of Ga...", the tribal name now partially unreadable. Scholars Damian McManus, writing in 1997, and the earlier Power et al. survey of 1992 both reference the stone, placing it within a broader corpus of early Christian period inscriptions from Munster. More recently, it has been digitised and studied as part of the Ogham in 3D project run by the School of Celtic Studies at the Dublin Institute for Advanced Studies, which has produced high-resolution three-dimensional scans of ogham stones across Ireland and beyond.

The stone's present location is recorded as Dublin South City, though the notes do not specify the precise building or institution where it is currently held. Anyone wishing to examine the inscription closely would do well to consult the Ogham in 3D database at the Dublin Institute for Advanced Studies before visiting, as the project provides detailed records including the three-dimensional scan, which can reveal the notches and strokes of the script more clearly than a photograph or a casual glance at the physical surface. The partial inscription, with its tantalising cut-off, is a reminder that even carefully preserved objects carry their losses with them.