It is called St Patrick's Bed, a name that conjures something domestic and faintly absurd for what is most likely the ruined remains of a megalithic tomb, the kind of prehistoric monument built from large standing stones, sometimes capped with a massive roof slab, that dots the Irish landscape in various states of survival. This one survives poorly. No roofing stone remains. The structure is long and narrow, a sub-rectangular cairn running roughly north-north-west to south-south-east, revetted on its west and north sides by upright stones, with two slightly curving rows of smaller uprights extending westward from its corners. What it once looked like in full is a question that has frustrated observers for well over a century.

When the antiquarian William Borlase examined the site in the late 1880s, he measured it at roughly 21 feet long and 4 to 5 feet wide, noted that its proportions were too narrow for a church, and concluded, with admirable candour, that he could not say with certainty what it had been, while finding it equally difficult to imagine what else it could have been if not a dolmen. Part of the confusion owes something to deliberate disturbance. John O'Donovan, visiting in 1837, recorded local complaints that soldiers from the Ordnance Survey, the sappers, had removed stones from the monument in order to construct a trigonometric station on the hilltop. By Borlase's visit, whatever coherence the structure once had was already compromised. The name itself, first recorded by O'Donovan in the same year, most likely reflects early legends associating St Patrick with Uisneach, the hill being a place of considerable mythological and ritual significance in medieval Irish tradition. More recently, geophysical survey has added an unexpected layer to the picture: beneath and around the cairn lie the ghostly outlines of two enclosures, probably defined originally by wooden palisades, one underlying the cairn itself and a larger one encircling it, suggesting that the site's ceremonial use predates even the monument that now marks it.