The castle’s history stretches back to medieval times when the Howel family, who arrived in Ireland around 1180, held Carrickbyrne as part of their feudal obligations to the Valence lords. By the 15th century, ownership had transferred to the Walsh family of Castlehale in County Kilkenny, who shared ancestral ties with the Howels through Stephen Howel in the late 13th century. Records from 1619 show Walter Walsh died possessing both Castlehale and several properties including Courthoyle, whilst by 1640, Robert Devereux of Ballyshannon owned the castle along with 500 acres at Courthoyle and additional lands in the parish of Adamstown.

Today, only the ground floor and first floor survive beneath a collapsed barrel vault that once ran east to west. The remaining structure, measuring approximately 10.3 metres by 7.8 metres, showcases well-preserved granite quoins and a protective base batter. The original entrance likely stood in the eastern wall, where the embrasure has been broken out into a wide opening. A spiral staircase once occupied the southeast corner, though it has since been destroyed. The ground floor features six narrow loops or squints across three surviving embrasures, with an additional cross-loop visible in the stairwell; evidence of medieval defensive architecture designed to protect the castle’s inhabitants.

Archaeological details reveal further features of daily castle life, including a destroyed garderobe chute in the northern wall and corbels in both the north and south walls that once supported the first floor. A rectangular window survives in the western wall, whilst the northern wall contains an embrasure with a lintelled floor and destroyed window at its eastern end. Curiously, a hinge stone remains at the northern end of the eastern wall, hinting at the castle’s original internal layout. These ruins offer a tangible connection to centuries of Irish history, from Norman feudalism through to the plantation era, preserved in stone on the Wexford landscape.