Locally it was known as 'Killwee', and tradition holds that it served as a children's burial ground, one of those liminal places, found across Ireland, where unbaptised infants were laid to rest outside the boundaries of consecrated ground. What makes the site quietly disorienting is the way the historical record shifts beneath you: the Ordnance Survey map of 1838 shows a roughly square enclosure with a rectangular building at its centre, labelled simply 'Grave Yard'. By the 1922 edition, the shape has become circular, the building has vanished from the cartography, and the label reads 'Children's Burial Ground'. Whether the shape changed in reality, or the earlier surveyor simply recorded it imprecisely, is not resolved.

The enclosure measures approximately 39 metres north to south and 37.5 metres east to west, defined by an earthen bank faced in parts with dry-stone walling on both its interior and exterior sides. At the north-west, the inner face takes the form of a kerb of large stones. Some of this stonework appears to have been absorbed into a later system of field walls, which complicates any reading of the original fabric. A six-metre break in the bank to the west might suggest an entrance, though no formal entrance feature is visible. The interior sits slightly raised above the surrounding ground level, and at the centre a low square platform survives, likely the foundations of a small building or church. The place-name 'Killwee', recorded by Aldridge in 1969, probably derives from the Irish 'cill', meaning a small church or monastic cell, suggesting the site may have ecclesiastical origins considerably older than its role as a children's burial ground.

The enclosure lies at the south-eastern edge of Rathlackan, on a terrace overlooking the bay. The central platform is low and easy to miss, but once seen it anchors the whole space differently, turning what reads at first as a field boundary into something with a long and layered past.