The stone is an ogham monument, meaning it bears text in one of the oldest written scripts associated with the Irish language, rendered as a series of notches and strokes cut along the stone's edge. What makes this particular example unusual is its position: not tucked into a field boundary or churchyard, as ogham stones so often end up, but standing upright on the exposed summit of Dunmore, or An Dún Mór, a headland rising to around 100 metres above sea level.

When the antiquarian John Windele first recorded the stone in 1838, it was lying flat on the ground. A year later, in 1839, Chatterton noted that it had been re-erected, and upright is how it has stood since. The inscription reads ERC MAQI MAQI-ERCIAS (MU) DOVINI(A), a formula typical of early medieval ogham commemorations, naming a person and their lineage. By the time R. A. S. Macalister examined it in 1945, the second-to-last word had already become unclear, and the final letter A, while included in most earlier transcriptions, is no longer visible on the stone itself. The gradual erosion of the text lends a particular poignancy to earlier accounts that caught it in fuller form. T. J. Westropp, writing in 1910, went further than mere epigraphy, suggesting that Dunmore may have functioned as a ritual site, possibly a sanctuary connected to the goddess Duibhne, the figure from whom the Corca Dhuibhne people, and the peninsula itself, take their name.

The stone stands on the summit of the headland, which projects westward into the Blasket Sound. The inscription faces whatever weather comes in off the Atlantic, which may go some way towards explaining why portions of the text have faded beyond recovery.