Killeens, from the Irish cillín, are unconsecrated burial grounds, typically used for centuries to inter those excluded from churchyard burial under Catholic canon law: unbaptised infants, strangers of unknown faith, those who had died by suicide, and occasionally executed criminals. They occupy a quietly sorrowful category of site, neither fully domestic nor fully sacred, often found at the margins of townlands, beside old boundaries, or close to ancient earthworks.

These sites were not random patches of ground. Many killeens occupy locations with far older associations, occasionally prehistoric enclosures or the sites of early medieval cillíní, the small monastic cells from which the word ultimately derives. The practice of using them persisted in rural Ireland well into the twentieth century, partly out of necessity and partly out of a folk theology that placed unbaptised souls in a liminal state, neither damned nor fully received into heaven. Parents who buried children in killeens often did so quietly, sometimes at night, without clergy. The grief attached to these places was real and unacknowledged in equal measure. In Mayo, a county shaped by successive waves of displacement and loss, such sites are not uncommon, and the one at Drumneen carries that same character of silent, unofficial mourning that defines the type across the west of Ireland.