Sites of this kind, known in Irish tradition as cillíní, were used for the burial of unbaptised infants and others who were excluded from consecrated ground under canon law. What makes Caherlehillan unusual is not simply its existence but what systematic excavation revealed beneath and within it: a community that marked its dead carefully, with plain stone markers above and, in many graves, deliberate placements of quartz pebbles below.

The site was investigated over more than a decade as part of the undergraduate training programme of the Department of Archaeology at University College Cork, with fieldwork running between 1992 and 2004 under the direction associated with John Sheehan, whose reports on each season are the primary record of what was found. The graves themselves were of two types, stone-lined cists and simple dug examples, both forms well attested in early medieval Irish burial practice. The quartz pebbles placed within them are harder to explain with certainty; quartz appears repeatedly in early Irish funerary and ritual contexts, and its presence here suggests something intentional rather than incidental. More surprising still was the discovery, beneath the burial ground, of structural evidence for a wooden church, an early building type that rarely survives above ground but whose post-holes and beam-slots can persist in the soil for centuries. Two carved cross-slabs were also recovered from the site, adding to the picture of an organised, if modest, early Christian community using this ground with care and purpose over a considerable period.