Duncarbry Castle, Duncarbry, Co. Leitrim

This McClancy stronghold was ideally positioned to monitor the crucial gap between Lough Melvin and Donegal Bay, roughly 5.5 kilometres wide, controlling an important route through the region. The castle likely consisted of a tower house surrounded by a bawn, a fortified enclosure typical of Irish castles built between the 15th and 17th centuries.

Today, visitors will find a rectangular grass-covered platform measuring 28 metres east to west and 17 metres north to south, its perimeter defined by collapsed walls that still rise over two metres high in places. At the northeast corner, a mound of rubble marks where the tower house once stood; its remains form a rectangular heap roughly 9.5 by 5.9 metres. Though no architectural features or wall facings survive, historical records tell us this was where Cahir Mac Flannchadha, heir to both William McClancy and the chieftainship of Dartry, died in 1538.

The castle's decline was gradual but thorough. As late as the 19th century, Samuel Lewis recorded that a gable wall with an arched doorway still stood amongst the ruins, but even this has since vanished. What remains offers a glimpse into the turbulent world of Gaelic lordship in early modern Ireland, when powerful families like the McClancys built fortified residences to protect their territories and project their authority across the borderlands between Ulster and Connacht.