By 1840, when the Ordnance Survey letters recorded its condition, that fragment of the north wall was essentially all that remained of a medieval parish church. Beside it stood a dry well associated with St. Senan, one of those small, often neglected holy wells, sacred springs or pools with pre-Christian and early Christian associations, that appear throughout the Irish countryside. The well had already gone dry by the time it was noted, and the church itself had been destroyed nearly two centuries earlier, in 1641.

The parish name turns up in records as early as 1201, variously spelled across the centuries: Kellonchon, Killonwyn, Kyllonchan, and several others, reflecting the inconsistent transcription of Irish place names into Latin and English administrative documents. The scholar T. J. Westropp, drawing on John O'Donovan's earlier work, linked the name to a St. Onchu, whose feast day falls on the 8th of February, suggesting the site's origins lie in the early Irish church rather than the later medieval period. Around 1223, a Norman lord named Geffry de Mareys did homage to Bishop Hubert for the townland, indicating that by the early thirteenth century the site had been drawn into the feudal administrative structures the Normans imposed across Munster. The Civil Survey and Down Survey maps of the 1650s record the name in several forms, confirming it was still a recognised place in the landscape even after the church's destruction during the upheavals of 1641.

The site lies within the baronies of Pubblebrian and Coshmagh in south County Limerick. Anyone visiting should expect very little in the way of standing fabric; the interest here is less visual than archaeological and toponymic. The remains, such as they are, sit in what is broadly agricultural country, and locating them requires some patience with older maps and local knowledge. The dry well of St. Senan, noted near the church ruin, may be difficult to identify on the ground given its condition when last formally recorded. The site rewards those with an interest in the layers of naming and ownership that accumulate around even the most fragmentary medieval remains.