The children's burial ground at Letterass in County Mayo is one such place. These sites occupy a peculiar position in the Irish landscape, neither fully sacred nor wholly forgotten, tended quietly by local memory long after the practice that created them faded away.

The use of cillíní reflects a theology that hardened during the medieval period and persisted in rural Ireland well into the twentieth century. Unbaptised children, according to the doctrine of limbo, could not enter heaven, and so the Church withheld the rites that would have permitted burial in a parish graveyard. Families instead turned to marginal ground, places that carried their own older sanctity, boundaries, ancient earthworks, or simply the far corners of fields. The grief attached to these places was rarely spoken aloud, and that silence became part of what preserved them. At Letterass, the site stands as a physical marker of that history, a place where private sorrow accumulated over generations in a townland in the west of Mayo.