The enclosure is defined by an earthen bank, about two metres wide and one metre high, and within it the low uninscribed grave-markers and a central mound of loose stones point towards its use as a ceallúnach, a burial ground traditionally reserved for unbaptised children and others excluded from consecrated ground. Two bullaun stones, large rocks with rounded hollows worn or carved into their surface and long associated with early Christian ritual use, survive nearby; one lies about twenty metres to the south of the ruins, while a second now sits in the roadside fence some fifty metres to the north, having apparently been removed from the graveyard at some point.

The church is dedicated to St Fiachna, whose name translates as raven, and the scholarly threads attached to his identity lead in unexpected directions. He may be the same figure as Fiachra Goll of Clonfert in County Galway, a man whose father's line connected him to the Uí Bhairrche clan of the Laois and Carlow region. The seventeenth-century hagiographer John Colgan, working through this Fiachra's pedigree, raised the possibility that he was also the hermit Fiacre, whose cult spread widely through France and centred on Meaux. That link may seem a long reach from a ruined Kerry church, but it has a traceable echo: a French feast day of 30 August was introduced to the Irish calendar in the late twelfth century by the compiler of the Martyrology of Gorman, and it came to be observed at St Fiachna's well, which still lies about fifty metres to the east of the church ruins. In the nearby townland of Gearhanagoul there was also a celebrated bush associated with Fiachna. The parish of Kilcaskan, in which the site sits, straddles a county boundary in an unusual way; the Ordnance Survey noted that only a small portion of the parish lies in Kerry, with the original church and the greater part of its area falling in County Cork.

The early ecclesiastical enclosure, whose curving arc from west-southwest through north was captured on the 1841 six-inch Ordnance Survey map, is no longer shown on later editions of the same mapping. Within it sits a second, larger rectangular stone-walled enclosure measuring roughly 82 metres north to south and 62 metres east to west, a nineteenth-century addition with a pillared entrance gate at the northeast. The two concentric layers of enclosure, one ancient and organic in outline, one more recent and geometrically imposed, give the site a quality of compressed time that the low, unmarked graves do little to dispel.