What was once a cashel, a type of stone-walled circular enclosure associated with early medieval settlement, was later pressed into service as a children's burial ground, known in Irish tradition as a cillín, a place set aside for those who, for one reason or another, could not be interred in consecrated ground. Nothing of this survives above ground today; the cashel has been levelled entirely, and whatever markers once indicated the graves have gone with it.

The picture that survives comes largely from nineteenth-century cartography and the conflicting accounts it has generated. The 1841 first-edition Ordnance Survey six-inch map names the site 'Tonakilla Fort' and annotates a 'Burial Ground' within its perimeter, suggesting the cashel had been reused for burial. The same map marks additional 'Graves' immediately to the south of the enclosure, along with a cluster of stones labelled 'Gallauns', a term applied to standing stones, which may represent the remnants of a much older megalithic structure. By the time the 25-inch Ordnance Survey map was produced, the cashel appeared only as a roughly circular scarp, with the graves and gallauns noted as a 'site of' rather than a present reality. The County Kerry Field Club, however, placed the burial ground outside the fort entirely, and the Irish Tourism Association appears to have assumed the stones were within a burial enclosure when the mapping evidence points the other way. Notably, John O'Donovan, the nineteenth-century scholar who produced detailed field notes across Ireland for the Ordnance Survey, made no mention of a burial ground here at all, which complicates the picture further. The question of what, precisely, was buried where, and how the various elements related to one another, remains genuinely unresolved. Annagh church and its graveyard lie about 370 metres to the east, close enough to suggest a long history of sacred use across this stretch of ground.