What makes them arresting is not their size but their ambiguity: they may be prehistoric barrows, the kind of low, rounded burial mounds raised over the dead in the Bronze Age, or they may be purely ornamental earthworks fashioned when the estate was being landscaped after 1700. No one has yet settled the question.

The seven features sit within the post-1700 Deerpark of Killua Castle, the castle itself lying roughly 570 metres to the north-north-east. A ringfort, one of the circular enclosed settlements common across Ireland from the early medieval period, stands just 90 metres to the north, and the 1837 edition of the first Ordnance Survey six-inch map shows a separate, older "Old Deer Park" some 650 metres to the south, suggesting the estate's landscape was reorganised and extended across more than one phase. The earthworks were identified in aerial photography taken in November 2011, their circular forms showing clearly from above in a neat east-west alignment. A post-1700 ornamental monument was erected on the demesne roughly 270 metres to the north-north-east, which lends some weight to the theory that the whole arrangement reflects deliberate Georgian-era landscape design rather than ancient burial. Yet the proximity of the ringfort, and the fact that barrows are commonly found in loose groupings near other prehistoric features, keeps the older explanation alive. The honest answer is that both things could be partly true: prehistoric mounds repurposed and tidied into a decorative scheme by an eighteenth-century estate owner with an eye for a composed view.