When surveyed in 1840, this rectangular tower house still retained much of its defensive character, with the west and south walls reaching 20 feet high whilst the north and east walls varied between 10 and 12 feet, suggesting the structure once stood considerably taller. The building represents what architectural historian Donnelly classified as a Type 5 tower house; a unique rectangular design that nonetheless incorporated the characteristic features of Irish Gothic military architecture.

The castle’s documented history stretches back to at least 1302, when it appeared in records as ‘Lismaceyre’, an appanage of Keynsham. Throughout the centuries, it passed through numerous hands, creating a paper trail of ownership that reads like a who’s who of Anglo-Irish nobility. In 1582, William Lacy received a pardon for the property, though James Reough Lacy held the actual castle. It was subsequently granted to F. Berkeley, who leased it to Edmund Drew, and by 1615, Maurice Berkeley had settled it upon his wife with reversion rights to his brother Henry and their sisters. The 1654-56 Civil Survey grimly noted it as ‘a ruinated Castle’ under the ownership of Lord Brohill, an English proprietor, indicating the structure had already fallen into disrepair by the mid-17th century.

Despite centuries of decay, the castle retains intriguing architectural details that hint at its former sophistication. Much of the vault over the second storey has survived, even after losing its northeast corner and upper levels. The original entrance faced south and was accessed via a straight stair built into the east wall. Archaeological surveys suggest there may have been a projection at the northwest corner, possibly a defensive turret or garderobe. The castle appeared on the 17th century Down Survey map of Connello Barony, and local tradition long held it as a de Lacy stronghold, linking it to one of medieval Ireland’s most influential Norman families.