The place is called Knockaunacroghera, an Anglicisation of the Irish Cnocán an Chrochaire, meaning roughly "the little hill of the hangman" or "the gallows hillock." That name alone suggests a grim past, but the tradition attached to the site adds another layer: that this is a Spaniards' grave, a place where men from the Spanish Armada were buried, or hanged, or both.

The barrow itself is a prehistoric earthen monument, the kind of low, flat-topped circular mound raised over burials in the Bronze Age or earlier. It sits at the centre of a subcircular platform roughly twenty-two metres across, edged by a low scarp, with the mound rising to between 1.1 and 1.4 metres at its highest point and measuring about twelve metres across at the base. The site appears by name on Ordnance Survey maps from 1842 and again on the 1920 edition. The antiquarian Thomas Johnson Westropp, writing in 1900, recorded the local belief that this was a "Spaniards' grave," where dead from the Armada had been interred. A later map by Tim Robinson, published in 1977, adds the more specific claim that Armada men were hanged here in 1588. The convergence of a gallows place-name, a prehistoric burial mound, and the wreck-strewn coastline of Clare in that terrible autumn of 1588 makes for an uneasy combination. Following the failure of the Armada, hundreds of Spanish sailors were drowned or executed along the west coast of Ireland, and local memory, for centuries afterwards, folded those deaths into the landscape in ways that were not always historically precise but were rarely invented from nothing.

The mound stands in open pastureland and is visible from a distance owing to the elevation of the hillock it occupies, which commands wide views of the surrounding countryside.