The ruin is modest in scale, just under fifteen metres long internally and less than five metres wide, built from roughly dressed rubblestone set in lime and sand mortar. What makes it quietly remarkable is not its architecture, which is fragmentary at best, but its claimed connection to one of the most dramatic deaths in late Elizabethan Ireland.

The church appears as 'Kilmanna' in the papal taxation records of 1302 to 1307, where it was valued at ten shillings per annum within the Deanery of Ardfert, placing it firmly in the medieval ecclesiastical landscape of Kerry. By 1837, local tradition had attached a more turbulent history to the site. Samuel Lewis, writing that year, recorded that the ruins were popularly known as Desmond's Chapel, and that the remains of the Great Earl of Desmond, Gerald FitzGerald, who was killed in 1583 during the Desmond Rebellions against the English crown, were said to have been interred here. FitzGerald had been one of the most powerful Munster lords of the sixteenth century, and his death effectively ended the old Geraldine order in the south of Ireland. Whether the burial tradition is historically verifiable is another matter, but the association had clearly taken root in local memory by the nineteenth century. By 1841, when the antiquarian John O'Donovan recorded the church for the Ordnance Survey, it was already a ruin giving its name to the surrounding townland, its east gable breached almost to the ground, the remaining north wall standing to a height of roughly nine feet.

A survey carried out in 2011 found the site in poor condition, with overgrowth particularly heavy at the eastern and western ends of the ruin and the tomb constructions of later centuries having disturbed what remained. The hillock position does afford wide views westward, and the church still commands its small piece of elevated ground above the Cordal Stream valley, which perhaps explains why it was chosen as a burial place in the first instance, and why it has continued to serve that function across the centuries since.