The crossing at Athassel Abbey in County Tipperary is exactly that: a flat, unguarded limestone span, just over twenty-five metres long and not quite four metres wide, laid across what was once a river or mill race and is now little more than a marshy bed. There are no railings, no raised edges, nothing to stop a distracted walker from stepping sideways into the wet ground below. Four arches carry the structure, each of equal width and height, their voussoirs, the wedge-shaped stones that lock an arch together, cut roughly and set on edge, resting on timber plank centring during construction. The whole thing curves gently at its western end, splaying off to the north and south, a detail that suggests some deliberate accommodation of the approach rather than a purely functional straight line.

The bridge almost certainly dates to the first half of the thirteenth century, built in a single phase to serve the gatehouse of Athassel Abbey, which it leads to directly on its eastern side. Athassel was an Augustinian priory, once among the largest monastic houses in Ireland, and the bridge would have been the formal approach to its entrance. By the late nineteenth century it had fallen into a sorry state. A writer named White, recording a visit in 1892, noted that the bridge was broken to the point where winter visitors were wading ankle-deep through swamp to reach the buildings, adding with evident satisfaction that repairs were under way at the time of writing. Some alteration is visible at the north-west angle of the western span, and this work may correspond to that late nineteenth-century intervention.

The marshy ground that once made winter crossings so unpleasant is still there beneath and around the structure. Approaching in wet weather, it is easy to understand how a broken bridge could make the abbey effectively inaccessible for months at a time. The limestone rubble of the bridge is roughly coursed rather than finely dressed, giving it a functional, workaday quality that sits at some distance from the grandeur of the abbey complex it was built to serve.