The island sits at the eastern edge of a bay in the southeastern corner of Garadice Lough in County Leitrim. Local tradition has long associated the island with Myles ‘The Slasher’ O’Reilly, though this appears to be a case of mistaken identity. The actual figure connected to these ruins was likely Colonel Myles O’Reilly, also known as Maol Mórdha Mac Edmond O’Reilly, who served as sheriff of County Cavan when the 1641 rebellion erupted and became one of its key instigators.

Myles O’Reilly was a second cousin to Philip Mc Hugh O’Reilly, who would later command the Ulster rebel army during their final struggles against Cromwell’s forces. Following the Ulster rebels’ defeat at Scarriffhollis in County Donegal in June 1650, the remaining forces retreated to the remote landscapes of Fermanagh, Cavan and Leitrim. It was during this desperate period that Myles reportedly fortified several islands, including Crane Island. These defences would never face battle; Myles surrendered alongside the rest of the rebel army at Clogh Oughtar in April 1653 before departing for the Continent, where he died in 1670.

Today, visitors to the island can explore the atmospheric ruins of a rectangular bawn measuring 41 metres northwest to southeast and 23 metres across, enclosed by collapsed mortared walls that still stand about half a metre high in places. At the northern angle, the remains of a circular tower survive, complete with a doorway featuring an outer rebate and two gun loops, though one was vandalised in 2013 when dressed stone was stolen. A third gun loop can be found in the nearby bawn wall, whilst a cairn at the southern angle may mark the site of a second tower. These crumbling fortifications, now draped in grass and scrub, offer a tangible connection to the turbulent years when Irish rebels made their last stand against Cromwellian conquest.