That absence is, in its own way, the story. A large stone structure once stood here, substantial enough to attract the attention of antiquarians and archaeologists across more than a century, before being destroyed around 1970 and leaving no visible trace at ground level.

The structure first entered the written record in 1849, when a writer named Moore described it as a large slab, roughly 3.65 metres square, resting on top of several smaller slabs. That arrangement, a broad capstone elevated by supporting stones, is the basic form of a dolmen, one of Ireland's most recognisable prehistoric monument types, in which a large horizontal stone is raised above upright supports to form a chamber. The description was convincing enough that William Copeland Borlase included the Dangan site in his 1897 survey, "The Dolmens of Ireland", a significant catalogue of such structures across the country. The classification seemed settled. Then, in 1958, a J. Delaney submitted a report to the National Museum of Ireland concluding that the structure was probably not the remains of a megalithic tomb at all. Whether it was a natural formation, a field boundary, or something else entirely was not recorded in any surviving detail. The site sat in that ambiguous state, neither confirmed monument nor dismissed curiosity, until it was destroyed around 1970. No excavation appears to have taken place beforehand, and whatever the stones might have clarified about their own origins went with them.