The five-storey rectangular tower, measuring 9.4 metres northwest to southeast and 12.9 metres northeast to southwest, rises from a strategic position bounded by a deep ravine to the west and sharp drops to the east and north. Built from uncoursed rubble stone with limestone detailing, the castle has survived centuries of conflict and changing ownership, though it required extensive repairs in the 1840s by Mr Furlong, the Earl of Devon’s agent, and more recently by the Irish state, which now maintains the site.

The tower’s interior reveals a sophisticated medieval design, accessed through a pointed-arch doorway that leads into a vaulted lobby complete with a murder hole overhead. A spiral staircase in the eastern corner connects all five floors, each serving different purposes; from defensive chambers with tall window embrasures on the lower levels to more comfortable living quarters above. The main first and third floor chambers feature rounded wicker-centred vaults, whilst the fourth floor contains segmental-arched windows with reconstructed double ogee-headed lights, a fireplace, and access to additional mural chambers including a garderobe. The renovations have preserved many original features whilst adding necessary elements like window lights, door surrounds, and stone flagging over the vaults.

Local tradition suggests the O’Hallinan clan built this formidable fortress around 1462, though it quickly fell to the O’Briens and later the Geraldines, the earls of Desmond. Following the Desmond Rebellions of 1569-73 and 1579-83, the Crown confiscated the castle, and in 1591 Queen Elizabeth I granted the estate to Sir William Courtenay, Earl of Devon, as part of the Munster Plantation. By 1655, the Civil Survey recorded it as ‘a ruinous Castle unrepaired’, though the substantial restoration work carried out since then has ensured this remarkable example of late medieval Irish tower house architecture continues to dominate the Limerick landscape, offering visitors a tangible connection to five centuries of turbulent Irish history.