The church walls, measuring 14.6 by 5.9 metres internally, remain intact and showcase the typical building techniques of 17th-century Irish ecclesiastical architecture; rubble walls reinforced with dressed stone corners, though curiously only the southwest and northwest corners received this treatment. What makes this site particularly intriguing is the evidence of architectural recycling; punch-dressed blocks embedded in the walls, along with a doorway featuring stop-chamfered jambs and a pointed arch in the western gable, appear to have been salvaged from an earlier medieval church that once occupied this spot.

The building’s fenestration tells its own story of changing uses and modifications over time. Four round-headed windows with splayed openings pierce the south wall, whilst the east gable contains a larger blocked window with a flat rear arch, and two more blocked windows can be traced in the north wall. Inside, the Office of Public Works has installed a high cross against the north wall on a specially constructed plinth, preserving this important early Christian monument within the protective shell of the later church. The remnants of an 18th-century memorial to the Olphert family, once an elaborate aedicule dating from 1754, now exists only as broken columns and moulded fragments cemented to various window sills; the inscribed tablet that once proclaimed the family’s prominence has vanished entirely.

This waterlogged site may hold deeper historical significance than its modest ruins suggest. The antiquarian John O’Donovan believed this location to be Rath Finan, an early ecclesiastical settlement that would predate the current structure by several centuries. Whether repaired or completely rebuilt after 1622, as Royal Commission records suggest, Raymunterdoney Old Church stands as a palimpsest of Irish religious history; medieval stones supporting post-Reformation walls, protecting ancient crosses, and bearing witness to centuries of continuous worship in this corner of County Donegal.