Though the MacMahons held sway as chiefs of Dunmugyda Inver during the 13th century, the castle itself doesn’t appear in records until 1574, when it belonged to Sir Donal O’Brien. By 1599, it had returned to MacMahon hands, only to be retaken by the Earl, who granted it to Morrogh MacGucarrick in 1617. Letters suggest someone still occupied the castle as late as 1698, but by the early 19th century, it had fallen into ruin.

What remains today is a rectangular tower house measuring roughly 11 metres east to west and 8.3 metres north to south, rising to about 13 metres in height. The structure originally stood two storeys tall, though much of the upper levels have since collapsed. Visitors entering through what was once the eastern doorway would have passed through a lobby protected by a murder hole above; a defensive feature that allowed defenders to attack intruders from overhead. The ground floor chamber featured a vaulted ceiling running east to west, with embrasures and double-splayed windows on the north and west walls, whilst the south wall was later modified to include a secondary entrance.

The castle’s internal layout reveals the complexity typical of these defensive structures. A mural staircase in the east wall connected to a spiral staircase at the southeast corner, leading to various chambers including a small room with two lights in the south wall. The first floor, also vaulted, could be accessed through a doorway in the eastern passage, though its western wall has since collapsed. A passage in the north wall led to a garderobe with two chutes; a medieval toilet system that discharged waste outside the castle walls. Whilst the spiral stairs once continued to upper floors, these levels are now lost, leaving only the sturdy lower portions to hint at the castle’s former grandeur.