Sir Frederick Hamilton arrived in County Leitrim in the early 1620s with a modest land grant of 5,000 acres, but his appetite for territory proved insatiable; by 1631, he’d amassed over 16,000 acres through various means. The centrepiece of his new domain was this formidable castle, likely completed around 1636, which served as both his residence and a symbol of English authority in this contested borderland.

The castle’s U-shaped design reveals Hamilton’s priorities: defence mixed with a desire for comfortable living. The main rectangular house stretched 20 metres east to west, flanked by two projecting wings that created a protected courtyard. Four corner towers, some rising to five storeys, provided both defensive positions and additional living space, each equipped with windows, gun loops, and even the occasional fireplace. The ground floor’s large mullioned windows suggest Hamilton wasn’t entirely expecting trouble, though the strategic sallyport hidden at the centre of the south wall hints at contingency planning. When Irish rebels besieged the castle in January 1642, burning the town but failing to breach the castle walls, Hamilton’s architectural choices proved sound; the siege lasted until April before the attackers gave up.

Today, the ivy-clad ruins stand within the remnants of a bawn wall that once enclosed a courtyard measuring 59 by 37 metres. Though much of the dressed stonework has been robbed over the centuries, including most of the quoins and window surrounds, the castle’s bones remain impressive. Archaeological excavations have uncovered evidence of cobbled courtyard surfaces and basement structures, whilst conservation work has stabilised what remains. The castle met its end not through siege but politics; the Earl of Clanrickard burnt it in 1652, five years after Hamilton’s death in Scotland, closing this chapter of plantation history in north Leitrim.