The stone is one of four ogham stones found within the souterrain at Lismore, known in Irish as An Lios Mór, and the particular interest of this one lies in what cannot yet be read. Ogham is an early medieval script, typically carved as a series of notches and scores along the edge or face of a stone, most often recording personal names in an archaic form of Irish. This stone, however, remains embedded in the structure around it, which means its full text may never be recoverable without disturbing the very monument it has been built into.

The stone was not identified until 2014, at which point it was found to be acting as a lintel on the chamber side of the passage leading to the northern chamber of the souterrain. A souterrain is an underground stone-lined passage or series of chambers, typically associated with early medieval settlement sites, and often found, as here, within a ringfort. Lismore is a multivallate rath, meaning it is enclosed by not one but three banks and corresponding ditches, set on rising ground with a wide outlook over the surrounding countryside. An opening was made into one of the chambers in the late 1970s, which has left the drystone construction of the walls and tunnels unusually visible. The stone itself measures at least 0.74 metres by 0.22 metres by 0.13 metres, though its full dimensions are unknown given how deeply it sits within the structure. What can be made out of the inscription is fragmentary: a broad-scored letter that may be an S or a C, a possible vowel notch representing A, and a cluster of three or four faint scores that could indicate V, T, S, or C. Whether these are the beginning or the end of a word, or name, remains unresolved. The stone has since been examined as part of the Ogham in 3D project, run by the School of Celtic Studies at the Dublin Institute for Advanced Studies, which uses three-dimensional scanning to record and analyse inscriptions that are difficult or impossible to read by eye alone.