What is now part of the Convent of Mercy school was once marked on maps simply as "Fever Hospital", a designation that would have carried considerable dread for the town's nineteenth-century population. Fever hospitals were established across Ireland during this period to isolate those suffering from typhus and other infectious diseases, separating the sick from the rest of a community that had little other defence against contagion. By 1906, when the next Ordnance Survey revision came around, the building had become a school, and by 1937 it was mapped as such again, the earlier function quietly erased from the official record if not from the fabric of the structure itself.

The building is a rendered, rectangular block running north to south, gable-ended and two storeys high, with chimneys sitting on both gables and two further chimneys placed off-centre along the roof. The front elevation, facing east, presents three bays, with slim double sash windows retaining their glazing bars and limestone sills, and a central door opening now fitted with a modern replacement. The rear elevation follows much the same arrangement, with the addition of a central porch. Windows have been inserted into the north gable at both ground and first-floor level, while the south gable has been absorbed behind a later addition. The 1842 Ordnance Survey six-inch map is the earliest documentary evidence for the building in its original function, placing its construction sometime in the decades before that survey, a period when fever hospitals were being established in Irish towns under a combination of local initiative and central government pressure.