The name itself is the first clue: killeen, from the Irish cillín, refers to a small, unconsecrated burial ground used historically for the interment of unbaptised infants. These sites exist across Ireland in considerable numbers, occupying margins both literal and symbolic, placed at the edges of townlands, beside old boundaries, or within the ruins of early ecclesiastical enclosures. They were not churchyard burials. Catholic doctrine, as it operated for centuries in rural Ireland, held that unbaptised children could not be buried in consecrated ground, and so families found other places, often ancient ones, carrying their own residual sanctity from earlier times.

The cillín tradition reflects a long negotiation between official religious practice and older, more local ways of understanding the dead and the landscape. Parents who lost newborns, stillborn children, or infants who died before baptism could not grieve through the formal structures of the Church, and so these quiet plots became places of unofficial mourning. Many killeens were used across generations, their locations passed on by word of mouth rather than recorded in any register. The Clare example at Killeen sits within this widespread but often poorly documented tradition, one of many such sites that survive in the landscape without fanfare, marked sometimes by a scattering of small stones or a slight depression in a field, sometimes by nothing visible at all.