It was found within a ringfort at Garranes in County Cork, and scholars believe it was originally housed in the site's souterrain, an underground stone-lined passage typically used for storage or refuge. That it ended up in the city at all is a reminder of how frequently these monuments were moved, repurposed, or rescued over the centuries, often ending up in museum collections far from where they were first raised.

The stone is substantial, measuring five feet nine inches tall and just under two feet wide, and carries an inscription that has occupied epigraphers for generations. R.A.S. Macalister, writing in 1945, read it as C[A]SSITT[A]S MAQI MUCOI CALLITI, a formula typical of early ogham stones in Ireland: a personal name, followed by maqi, meaning "son of", and mucoi, indicating tribal or kin group affiliation. The name CALLITI identifies the kin group, while the personal name at the head of the inscription presents a small puzzle. Macalister restored it as CASSITTAS, but Damian McManus, revisiting the stone in 2004, agreed with the general reading while noting that the first name could plausibly end in either -AS or -OS, a distinction that matters for understanding the name's linguistic origins and the date of the inscription. It is a small uncertainty, but one that reflects the careful, ongoing nature of ogham scholarship.