This intriguing structure stood on the western side of North Main Street, where in 1782 it caught the attention of Cooper, who described it as ‘a small square castle of very ancient appearance’. Historians have debated its exact nature; it may have been either a fortified house or a compact tower house, typical of medieval Irish defensive architecture.

The castle’s exact location remained something of a mystery until 1997, when routine archaeological monitoring during pipe trench excavations unexpectedly revealed substantial stone foundations. These discoveries confirmed what local historians had long suspected about the castle’s position. The excavations uncovered the base of a building measuring approximately 19 metres wide externally and 13.5 metres internally along its north-south axis. Among the most interesting finds was a cobbled surface near the northern end of the structure, which archaeologists believe marks an original entrance through the eastern wall.

The foundations tell us something about the castle’s relationship to the medieval street layout of Naas. The wall remains sit between 6.4 and 7 metres east of the current street building line, following a gentle curve from north to south. Historical records suggest that a Bridewell, a type of prison common in Ireland from the 16th century onwards, once stood nearby, hinting at the area’s long history as an important civic space in the town. While Lattin’s Castle itself has vanished from the landscape, these archaeological traces offer a tangible connection to Naas’s medieval past.