These small, unconsecrated plots were used for centuries to inter unbaptised infants, and occasionally others considered ineligible for burial in sanctified ground, including stillborn children, young mothers who died in childbirth, and sometimes strangers or suicides. They occupy a distinct and often melancholy place in the Irish landscape, set apart from parish graveyards, frequently sited near old boundary ditches, ringforts, or the ruins of early medieval churches. Their locations were chosen with care, kept within living memory by families and communities rather than recorded in any official register.

The practice of burying unbaptised children in cillíní was rooted in the theological position, observed rigidly for much of Irish Catholic history, that those who died without baptism could not enter consecrated ground. The grief surrounding these burials was largely silent; no funeral Mass, no public mourning, often no marked grave. Parents would carry an infant to the cillín in the early morning or at night, burying the child quietly. The sites themselves are usually modest, sometimes identifiable only by a slight rise in the ground or a scattering of small stones. Many have never been formally excavated or documented in detail. The one at Coolcronaun is among hundreds recorded across the country, each representing private losses accumulated over generations.

Because detailed documentation for this particular site is not yet publicly available, specific information about its extent, condition, or precise location within the townland remains difficult to establish. Coolcronaun lies in the west of Mayo, a county with a high density of such sites relative to its population, reflecting both the depth of local tradition and the scale of rural poverty and infant mortality in earlier centuries. Anyone with a family connection to the area, or a broader interest in post-medieval folk practice, would find the wider landscape worth studying attentively.