The two-storey rectangular structure, complete with twin towers on its eastern façade, guarded a causeway that crossed the defensive moat surrounding the abbey. Founded in the late twelfth century as a dependency of the Abbey of St. Taurin in Normandy, Fore Abbey earned local fame as one of the town’s ‘seven wonders’, particularly for being an ‘abbey built on a bog’; a claim that archaeological excavations in 1992 proved remarkably accurate.

The gatehouse reveals centuries of adaptation and conflict through its architecture. Its ground floor features barrel vaulting divided into two chambers, each with its own fireplace and windows, whilst the northeastern tower originally rose three storeys high with small chambers on each level. During raids by the O’Reillys and O’Farrells in the 1420s, the building was incorporated into the town’s fortifications; its original entrance archway was blocked and relocated to the southern side, and a garderobe tower was added to the northeast corner. The excavations uncovered fascinating construction details, including parallel lines of post and wattle fencing built directly on the bog to create a pathway across the difficult terrain, and timber piles driven into the peat to support the later garderobe tower.

By 1815, paintings show the gatehouse in ruins, but it was reconstructed around 1850 when a stone porch was added and a new doorway was knocked through the blocked medieval archway. The archaeological work revealed multiple occupation phases, from thirteenth-century pottery sherds and a bone die found in the earliest levels, to nineteenth-century tiled floors laid by later occupants who substantially rebuilt the interior foundations. Today, the gatehouse stands as a testament to medieval engineering ingenuity; its builders managed to create stable foundations on bogland using layers of stone and compact clay, establishing a structure that has endured for over seven centuries.