The Ordnance Survey letters of that year describe the south wall rising to about eleven feet, its rubble construction of large and small stones bound with gravel and lime mortar still holding together, while the rest of the building had sunk so far into the earth that only the ghost of a foundation could be traced. What made the surveyors pause was the doorway on that same south wall: despite being badly disfigured on its outer face, the inner arch survived, formed of thin flags in the pointed style, and the carved blocks still carried traces of a round-headed, moulded doorway decorated with rosettes, suggesting construction or significant reworking around 1500.

The place-name itself turns up in records stretching back to 1291, appearing under various spellings, among them Dunmolyn, Donmelyn, and Dunmuilin, before settling into something closer to its modern form. The church had connections to Manisternegaylagh, a monastery in the wider area, and by 1452 it appears in a rental document associated with the O'Connell territory. A survey of 1657 noted the walls still entire, with a west window and a south door both present, meaning the substantial collapse happened in the roughly two centuries that followed. In May 1670, Dunmoylan was among the lands granted to Sir T. Chambrelan under the Act of Settlement, the post-Cromwellian mechanism by which ownership of Irish land was redistributed on a massive scale. The 1658 Down Survey map of the Barony of Connello also depicts a tower-house beside the church, a fortified residential structure typical of late medieval Munster, positioned in the north-east quadrant of the Dunmoylan townland.

Visitors approaching the site today should be aware that the archaeological record points to several layers of interest within a small area. To the north of the church lies a nearly levelled dun, a circular enclosure of pre-Norman origin, measuring some ninety feet across, though it has been reduced almost to ground level. Close to the church is Tobereendowney well, a holy well, the type of site, essentially a spring with long-standing religious or folk associations, that frequently occurs alongside early Irish ecclesiastical foundations. The inner arch of the south doorway, with its thin flag construction, remains the most legible piece of fabric on the site, and the carved rosette blocks noted by Westropp in his 1904 to 1905 survey are worth examining closely if any masonry survives in situ.