At the foot of the Comeragh Mountains, where the uplands give way to the flood plain of the River Suir, a single surviving wall stands beside a public road with a plaque reading "Clonmel Spa". It is an odd thing to encounter: a remnant just three metres high, its pointed doorway bricked up, surmounting what were once the foundations of a circular domed wellhouse. The structure served this well for centuries, and the well itself is older still, moving through several identities, from holy well to fashionable medicinal resort and back again to near-obscurity.

The well appears to have begun its recorded life as a holy well, one of the sites across Ireland where patterns were held, meaning seasonal gatherings combining religious devotion with communal festivity, often on a saint's feast day. According to the Reverend Patrick Power's study of Decies placenames, these patterns continued into the nineteenth century. But the well also attracted a more genteel class of visitor. Charles Smith, writing in the eighteenth century, noted that its waters were being taken medicinally, placing it within the broader European fashion for spa treatments that gave this corner of County Waterford its name. Power further suggests that a wellhouse was constructed around the spring in 1593, during the mayoralty of a William Stanley, which would make it a remarkably early piece of purpose-built civic infrastructure for a rural water source. That building, described locally as a domed circular structure of roughly four metres internal diameter, with stone benches lining the walls and a hand-operated pump at its centre, remained in use into the mid-twentieth century.

What remains today is the north wall of that wellhouse, about 1.2 metres thick and three metres tall, with the blocked pointed doorway still legible in brick. The Ordnance Survey mapped the site as a spa well on both its 1840 and 1923 six-inch editions, which suggests it retained enough local significance to be worth recording across nearly a century of mapping. The plaque naming it "Clonmel Spa" sits incongruously atop this stub of masonry, a small label for something that once drew people down steps into a cool, vaulted interior to take the waters.