These were places set aside, outside the boundaries of consecrated ground, for the interment of unbaptised infants and others who, under Catholic doctrine, could not be buried in a parish churchyard. The one at Turloughanbaun in County Mayo is one such site, its name quietly carrying the landscape it occupies: "turlough" refers to a seasonal lake, a distinctly Irish phenomenon where water rises and recedes through the limestone below, and "bán" suggests pale or white ground. That combination of a vanishing lake and a burial place for children who, in the eyes of the Church, occupied a kind of theological in-between, gives the site an atmosphere that is hard to put into words without reaching for the obvious.

Cillíní were in use from at least the early medieval period in Ireland and continued well into the twentieth century in some rural areas. The practice arose from the belief that unbaptised souls could not enter heaven, and so could not share consecrated ground with the baptised dead. Families buried their infants in liminal places instead: old ringforts, the banks of rivers, the edges of bogs, or sites with some pre-Christian association. In many cases, no formal markers were used, and the graves were known only through local memory passed between generations. At Turloughanbaun, the specific history of the site, its dimensions, the number of burials it contains, and any associated features, remains to be fully documented, but its classification as a children's burial ground places it within this wider and deeply human tradition of quiet, unofficial grief.