Though local tradition long associated this stronghold with the FitzGeralds of Mayo, the castle’s true story belongs to the ambitious Dillon family. Theobald Dillon, descended from Sir James Dillon of Proudstown in County Meath, came to Connacht in 1582 as a government servant and shrewdly used his position to amass considerable landholdings around Loughglinn. By the time of his death in 1624, he had established an extensive estate that passed to his second son, Sir Lucas Dillon.

The original castle was an impressive square fortress with a tower at each corner, though time has not been kind to the structure. By the 18th century, only two towers remained standing, and today just one survives. This three-storey circular tower rises approximately 10 metres high, with metre-thick walls and an interior diameter of 3 metres. The ground floor features three gun-loops; practical defensive features that speak to the uncertain times in which it was built, whilst the upper floors have simple rectangular windows that are curiously rectangular internally despite the tower’s circular exterior.

The castle’s gradual dismantling wasn’t entirely due to natural decay. Many of its stones, including an inscribed plaque, were reportedly incorporated into the construction of Loughglinn House, built about a kilometre to the east. This practice of recycling castle masonry for newer buildings was common across Ireland, transforming medieval fortifications into the building blocks of Georgian country houses. What remains today offers a tangible link to the Dillons’ rise to power in Connacht and the complex web of land ownership that characterised 17th-century Ireland.