Located about 120 metres southwest of the main abbey buildings, this remnant sits on the flood plain where the Campile River winds its way towards its estuary. The structure occupies a strategic position on the north bank of a small stream, roughly 50 metres east of where this tributary meets the main course of the Campile.

What remains today is the outer pointed arch of the gatehouse, an impressive feature standing approximately 4 metres high with a width of 3.35 metres. The arch, which retains its original plank centring, would have formed the main entrance passage for visitors approaching the abbey from the south. The thickness of the arch, at 0.82 metres, hints at the substantial nature of the original structure. Archaeological investigation has revealed the bases of two piers that once formed part of the eastern side of the entrance passage; these foundations now lie beneath the western wall of the later church building.

This gatehouse would have served multiple functions for the Cistercian community: controlling access to the abbey precinct, providing accommodation for the gatekeeper, and acting as a symbolic threshold between the secular and sacred worlds. Its survival, whilst the rest of the gatehouse complex has vanished, offers a tangible link to the medieval landscape of County Wexford and the once thriving monastic community at Dunbrody.