What was once an ancient fort, the kind of raised ringwork that would have served defensive or settlement purposes in early medieval Ireland, became, at some point, a burial ground for young children. The two uses are not as contradictory as they might seem; repurposing old enclosures as sacred or liminal spaces was not uncommon in Irish tradition, and the raised interior of an earthen mound offered a kind of natural demarcation from the surrounding land.

The site was noted by the scholar and topographer John O'Donovan during the Ordnance Survey work of 1838, when he recorded it as an ancient fort serving as a burial ground for young children. The Ordnance Survey map of that same year marked it as a circular enclosure containing a grave yard. These children's burial grounds, sometimes called cillíní, were used for infants who had died before baptism and were therefore, under prevailing Catholic practice of the time, excluded from consecrated ground. They tend to occupy marginal or ancient sites, places already set apart from ordinary use, and this enclosure at Cloonliffen fits that pattern. The burial ground occupies the interior of the earthen mound, meaning the old structure itself became the container for a community's quiet grief.