From the fourteenth century through to the seventeenth, the victims of successive outbreaks were buried here in the ground beside St. Nicholas's Lane and the Whitening Stream, in numbers enough to give the site a popular identity that has outlasted any formal dedication. That the ruin is tucked into the Old Bridge quarter, across the River Suir from the medieval town centre, may itself reflect the logic of epidemic burial, keeping the dead at a remove from the living.

The church has a quietly complicated history beyond its grim nickname. Despite the association with mass burial, it remained a functioning place of worship well into the post-medieval period, recorded as still in use in 1669 and identified by Lyons in 1952 as one of only two churches serving Catholic worship in Clonmel during the post-Restoration years, a period when Catholic practice in Ireland operated under significant legal constraint. The building itself is modest, measuring roughly 7.85 metres by 4.47 metres internally, with walls of randomly coursed sandstone rubble about 0.9 metres thick. Entry was through a pointed doorway in the north wall, and the interior held two single-light windows and a pair of aumbrys, small recessed wall cupboards used for storing liturgical vessels, one in the north-west angle and one south of the east window. Lyons also noted the traces of what appeared to be a conventual domestic building at the south-east angle, possibly indicating a religious community once associated with the site, though nothing of that structure now remains.

The west gable, topped by an ivy-covered bellcote, was already in a precarious condition when the site was inspected, with graffiti and scorch marks visible on the interior wall. The church sits in the north-west corner of a sub-rectangular graveyard, itself still present, which gives some sense of the original enclosed encampment of the dead this corner of the town once formed.