Look more carefully at the piers, though, and you begin to suspect something older is embedded in the structure. The arch-rings and parapet belong to one era, but the stout masonry underneath them belongs to another entirely, and the gap between the two is measured in centuries.

The story of a crossing here begins in January 1355, when Clonmel received a pontage grant from Edward III, a royal licence allowing the town to collect tolls specifically to fund bridge construction or repair. No record survives to pinpoint exactly where that fourteenth-century bridge stood, but a deed from 1388 refers to a plot of land in Clonmel bounded by the King's way leading to the great bridge on the west, and the most likely candidate for its location is where the structure now known as Old Bridge stands. By 1656, the Down Survey map of the walled town shows a bridge to the south of the settlement, and by 1714 it appeared on Moll's map as a key link on the road to Dungarvan and Cappoquin. A description from 1748 calls it a very spacious bridge of twenty arches spanning the Suir. The portion that survives today is considerably more modest: a three-span, slightly hump-backed crossing, 24.5 metres long and 8 metres wide, built from randomly coursed sandstone, limestone, and some granite. Originally just 5.5 metres wide, it was broadened by roughly a third around the mid-eighteenth century. Then in 1830, a local miller named Hughes removed a building that jutted onto the roadway at the southern end, widening the bridge further on the downstream side and prompting the addition of a new parapet. The cut-waters, the projecting wedge-shaped piers that break the river's current, are trapezoidal in plan; those on the eastern face carry a sharp edge, while their western counterparts are blunted and square. The voussoirs, the wedge-shaped stones that form the arch-rings, are so regular in their arrangement that the arch-rings themselves are thought to date no earlier than around 1750. But the underlying piers and the ratio of span to pier width point clearly to a much earlier core, onto which successive generations layered their own modifications and repairs.