These sites, known in Irish as cillíní (the singular is cillín), were informal, unconsecrated plots where unbaptised infants were laid to rest, kept apart from the main churchyard by the theological conventions of the time. Catholic doctrine held that unbaptised children could not enter consecrated ground, and so communities quietly maintained these separate spaces, often at liminal locations: old ringfort banks, shorelines, field boundaries, or the ruins of early medieval churches. The practice was widespread from at least the medieval period and continued, in some areas, well into the twentieth century.

The Doogort cillín sits within a landscape already layered with early Christian and prehistoric remains. Achill Island has a long record of settlement, and these children's burial grounds frequently occupy ground with much older associations, their placement reflecting a folk understanding that such liminal, anciently sanctioned places were appropriate for souls in an ambiguous spiritual condition. The grief surrounding cillíní was largely private; families buried their infants without ceremony, often at night, and the sites were rarely marked in any formal way. Over generations, many became overgrown or forgotten, their locations preserved mainly in local memory and in the placenames attached to surrounding fields.