Built by the Ferris family, who proudly served as ‘guardians of the line of the Laune’, this limestone fortress measures 14.8 metres east to west and 9.8 metres north to south. Though it lost its battlements over the centuries, the tower still stands to its full original height, its walls retaining much of their original harling despite extensive repairs carried out by the Office of Public Works in the 1940s when the corners were found to be dangerously undermined.

The castle’s defensive architecture tells the story of evolving military technology and domestic comfort. Entering through the pointed arch doorway on the east wall, visitors would have once encountered a yett, a Scottish-style iron grille gate whose chain hole can still be seen in the north jamb. The interior reveals a sophisticated layout: spiral stairs wind clockwise from the southeast corner, connecting the main chambers on each floor. The ground and first floors feature relatively simple windows with splayed embrasures, whilst the second floor boasts a fireplace and access to two corner bartizans; defensive turrets that project from the corners, supported by tapered corbels and pierced with gun loops. The third floor showcases the castle’s most elaborate features, including six windows, two of which display triple ogee-headed lights with carved spandrels depicting birds and leaf patterns, suggesting the space served as the lord’s private quarters.

After Murrogh McOwen Ferris lost the property during the Cromwellian confiscations of 1656, the castle passed to the Eagar family. By the 1840s, records mention a dwelling house adjoining the tower’s western side, though no trace remains today. Similarly vanished is the defensive moat that once encircled the castle, documented as late as the 1940s but now existing only in historical memory. Despite these losses, Ballymalis Castle endures as one of Kerry’s finest examples of late medieval tower house architecture, its weathered limestone walls still guarding the crossing point they were built to protect five centuries ago.