It is a lone survivor, and the inscription carved along its edges has spent centuries slowly flaking away, taking portions of a name, or perhaps a lineage, with it.

Ogham is an early medieval script, typically carved as a series of notches and strokes along the edge of a stone, used mainly in Ireland between roughly the fourth and seventh centuries to record names and genealogical claims. The Ballynabortagh stone carries its inscription along the south and southeast edges, but the lower portions have deteriorated badly. When the scholar R.A.S. Macalister examined it in 1945, he could recover only a partial reading, transcribed as probably ...UIVAIBES [...]RTAGNI, the brackets and ellipses telling their own story of what has been lost. The fragment ending in RTAGNI is suggestive of a personal name of the period, though certainty is out of reach. What makes the stone's situation stranger still is its context. By 1842, when the first detailed Ordnance Survey six-inch maps were being drawn, a square enclosure stood nearby, now completely levelled and gone. The map marked the stone as a 'dallaun', the Irish term for a standing stone, outside the northwest corner of that enclosure. Yet the antiquary John Windele, writing earlier, described four standing stones actually inside the enclosure, and Macalister concluded this was one of them. A second ogham stone from the same area is recorded separately, suggesting that what once existed here was not a solitary monument but a considered arrangement of stones, possibly marking territory, ancestry, or burial, now almost entirely erased from the landscape.