The site first appears on historical records in the 1655 Down Survey map of Farbill Barony, where it’s shown as a castle belonging to Thomas Darcy Esqr. of Lisnabin in 1641. However, even by the time of that survey, the original castle was already recorded as being “quite demolished”, suggesting its destruction occurred sometime during the turbulent years of the 1640s.

What visitors encounter today at Lisnabin is quite different from the medieval fortress that once stood here. The current structure is a 19th century castellated house, complete with decorative battlements and turrets that were fashionable during the Victorian Gothic Revival period. The 1913 Ordnance Survey map shows a rectangular building measuring approximately 17 metres by 14 metres, which corresponds to the present Lisnabin House. The surrounding farm buildings and walled garden all appear to date from the same 19th century period of construction.

According to the National Inventory of Architectural Heritage, there’s a tantalising possibility that fragments of the original medieval castle were incorporated into the Victorian structure, though no obvious traces of earlier stonework can be identified today. This practice of reusing medieval masonry was common among 19th century builders who sought to add authenticity and historical gravitas to their romantic recreations. Whether any genuine medieval fabric survives within the walls of Lisnabin House remains an open question, making this site a fascinating blend of documented history and architectural mystery.