Visible on aerial photography, they sit quietly in the landscape, and nobody is entirely certain what they are. They might be prehistoric barrows, the low, rounded burial mounds that dot the Irish countryside from the Bronze Age onward, later pressed into service as decorative features when the estate was being laid out. Or they might be wholly the invention of post-1700 landscapers, shaped from scratch to ornament the grounds of the castle. The question has not been resolved, and that ambiguity is rather the point.

Killua Castle lies about 570 metres to the north-north-east of the earthworks, and the wider estate was substantially developed after 1700. The 1837 edition of the Ordnance Survey six-inch map shows an 'Old Deer Park' roughly 650 metres to the south, suggesting the parkland evolved in distinct phases over time. The first edition OS map records tree groves and an old pathway running through the deerpark in the vicinity of the earthworks, which fits neatly with the idea that whatever these mounds originally were, they became absorbed into a designed landscape. A post-1700 monument was also erected on the demesne, about 270 metres to the north-north-east, adding another layer of deliberate estate ornamentation to the area. Ninety metres to the north of the earthworks sits a ringfort, one of the circular enclosures used for settlement and farming throughout early medieval Ireland, suggesting the ground here has been shaped and reshaped across several different periods.

The seven earthworks are clustered closely enough together, and arranged with sufficient regularity, that they read as a set rather than a scatter. Whether a prehistoric community placed their dead here in a row, or whether an eighteenth-century estate designer simply liked the visual effect of low grassy circles in a grove of trees, the result is the same: a peculiar alignment that refuses to give up a clear answer.