That it ended up serving as a lintel rather than standing upright, as ogham stones typically did, is only one of the curious things about the stone from Underhill in County Cork.

The stone, measuring 1.75 metres long and 0.7 metres wide, was found not alone but alongside two other ogham stones, all three of them within a souterrain, the type of stone-lined underground chamber or passageway commonly built in early medieval Ireland, often beneath a settlement or ringfort, and used variously for storage or refuge. The inscription is described as being in fine knife-cuts, and reads simply MOUNIN, a personal name of uncertain identity. Scholars including D. McManus, writing in 1997, and O'Kelly and Shee in 1968, have noted and catalogued it, though the name itself remains unelaborated in the historical record. The concentration of three ogham stones within a single souterrain at one site is unusual, and suggests that either the stones were gathered here deliberately at some point, or that the site held particular significance in the early Christian centuries when ogham was in use.

The stone is no longer at Underhill. It was removed to the National Museum of Ireland in Dublin, where it is held in the collection. Anyone wishing to see the inscription in person would need to make enquiries with the museum directly.