Fethard is a conspicuous exception. An oval circuit of limestone walling, nearly complete and enclosing roughly 7.5 hectares, still wraps around the older core of the town, standing in places to a height of nearly eight metres. Built wide enough to carry an internal wall-walk, the wall is composed of large, randomly coursed limestone blocks with rubble fill and pinning stones, and it retains a quality that is increasingly rare in an Irish urban context: the sense of an actual boundary, not merely a fragment.

The money to build such a wall came through murage grants, a medieval mechanism by which the Crown authorised a town to levy tolls on goods passing through in exchange for using the revenue to fund construction or repair of its defences. The earliest known grant for Fethard dates to 1292, with further grants from 1367 onward over at least a century. By 1608, James I's incorporation charter was still directing fines and forfeitures toward the upkeep of the walls and fortifications. The town originally had five gates, one for each access route, but only the North Gate at Sparagoulea survives. It was once taller, probably with a room above the round arch, but the upper courses were removed in the early twentieth century when they became unstable. Attached to its east side is a three-storey gatehouse, marked on the 1840 Ordnance Survey map as 'Currikeen Castle', with a barrel-vaulted uppermost floor and a finely detailed ogee-headed window at second-floor level on its south wall. The other gates disappeared mostly in the nineteenth century, though a house on Burke Street still contains a mural stone stair thought to be a remnant of the gatehouse that once led toward the Augustinian friary. There are stranger survivals too: set into the external face of the southeast angle of the wall is a sheela-na-gig, one of those enigmatic carved female figures found on Irish ecclesiastical and secular stonework whose precise function remains debated. A 1763 map by Miles Swiney records several mural towers that have since vanished entirely from the visible fabric of the town, leaving the circuit quietly altered from what it once was.

The south circuit of the wall, running from the corner of Holy Trinity graveyard to Convent Bridge, has been restored, and the three-storey mural tower in the southwest angle of the graveyard is accessible enough to reward close attention. This tower and the North Gate are both thought to date from the fifteenth century, likely funded by the later murage grants. The tower's first-floor chamber retains a pointed vault and six windows; a mural stair winds upward through the wall thickness to a second floor and then to a roof turret. Pottery recovered during excavation near the Barrack Street gate dates to the late thirteenth or early fourteenth century, which places the earliest phases of construction in the same period as the first known murage grant.