This O’Brien stronghold controlled the medieval Corofin-Gort road, known in Irish records as Bealach-an-Fiadhfhail. The castle’s strategic importance made it a target during the Tudor conquest; in 1569, Lord Justice Sir Henry Sidney besieged and captured it. Its owner, Mahon O’Brien, led an uprising against British rule in 1580 and received a pardon, only to die six years later when Sir Richard Bingham attacked the castle again, this time demolishing it. The lands passed through various hands until Turlough O’Brien seized them in 1599. Local legend claims an Irish flag flew from the ruins during the 1917 uprising until the RIC removed it.

Today, only the north wall and fragments of the east and west walls remain of this four-storey tower house, which once included a mezzanine level above the second floor. Built from limestone blocks with fine corner stones, the surviving north wall rises 21 metres high, complete with its original gable and sections of parapet. The structure reveals sophisticated defensive architecture; narrow arrow loops pierce each floor, whilst the upper levels feature elegant ogee-headed windows. The second-floor mezzanine contains an intriguing locked chamber accessible only by ladder, possibly an oubliette or secure storage room, with its own window cut into the thick walls.

The castle’s interior showcases the typical features of an Irish tower house, with vaulted ceilings, wall cupboards, and a garderobe in the northeast corner. The third floor, which served as the solar or private quarters, boasts a particularly fine double ogee-headed window with an intact mullion and decorative hollow spandrels. Above this, a wall-walk once ran around the entire structure, protected by a parapet with numerous drainage holes. Though storms in 1990 caused further damage and rubble now fills much of the interior, the remaining walls stand as testament to both the architectural skill of their builders and the turbulent history they witnessed.