These sites, known in Irish tradition as cillíní, were places set aside for the burial of unbaptised infants and others considered ineligible for consecrated ground under Catholic practice. The one at Raherneen occupies an irregular, unenclosed area roughly thirty metres north to south and fifteen metres east to west, its graves indicated by numerous set stones aligned east to west in the old Christian manner, oriented towards the rising sun.

The cashel itself, a type of early medieval stone ringfort with a roughly circular dry-stone enclosing wall, lends the site a considerable antiquity, though the burial ground within it was still in use well into the modern period. A single inscribed grave-marker from the eighteenth century survives, dedicated to the O'Daly family of Dunsandle, a notable local estate not far from Raherneen. The presence of a named, formal marker here is relatively unusual for a cillín, where burials were typically quiet, unofficial, and rarely commemorated in stone. That one family felt moved to erect such a marker, and that it has endured, adds a particular weight to this otherwise spare and overlooked corner of the Galway landscape.