These sites, known in Irish as cillíní (singular: cillín), were informal burial places reserved for those considered ineligible for consecrated ground under Catholic Church practice. The unbaptised, stillborn infants above all, were interred here quietly, often without ceremony, by families who nonetheless took care to find their children a place of some sanctity, frequently an ancient enclosure, a liminal boundary, or ground that carried its own older, pre-Christian sense of the sacred.

The practice was widespread from at least the medieval period through to the mid-twentieth century, and cillíní are scattered across the Irish landscape in the hundreds, perhaps thousands. They occupy threshold places, old ringfort banks, shorelines, and forgotten field corners. The grief that surrounds them was often private and unrecorded, which is part of why so many of these sites remain poorly documented. The Cloontubbrid example is one such place, formally recognised as an archaeological monument but awaiting fuller investigation and detailed recording.