Ogham is an early medieval script, common in Ireland from roughly the fourth to the seventh centuries, in which letters are represented by notches and strokes cut along the edge of a stone. The stones at Carhoovauler had been repurposed as structural elements inside an underground passage, the kind of dry-stone construction known as a souterrain, typically built as a place of refuge or storage beneath a ringfort or settlement. One of the three had been set upright as a pillar stone inside the first chamber of the souterrain, its inscribed edges presumably unremarked upon for centuries.

The discovery came in 1976, and the find was reported by McCarthy in 1977. The inscription on this particular stone was read by M. J. O'Kelly, one of the foremost Irish archaeologists of the twentieth century, as SCAMAGNI. Like most ogham inscriptions, this would represent a personal name in the genitive case, meaning roughly "of Scamagni", the kind of memorial formula typical of the period. The fact that three ogham stones ended up incorporated into a single souterrain suggests the builders had access to a local source of inscribed stones, possibly from an earlier burial ground or memorial site nearby, and saw no difficulty in making use of them as convenient building material.