Built during the 16th or 17th century, this rectangular fortified house measures 11.6 metres in length and 5.7 metres in width, constructed from roughly coursed masonry that has weathered centuries of Irish weather. The structure survives to first floor level and features a distinctive projecting turret at its northeast corner; a defensive element common to fortified houses of this period. An 18th century drawing by artist Beranger from 1766 captures the building in better condition, showing it as a substantial rectangular structure with its characteristic corner turret still prominent.

The castle’s main entrance presents an elegant round arched doorway with carved stone surround, complete with a protruding keystone and bar-bolt recess, though this entrance has since been blocked. The interior layout reveals thoughtful defensive planning: small rectangular windows provided minimal light whilst maintaining security, and the square corner turret rises two storeys with multiple access points at different levels. Particularly noteworthy are the musket loops positioned in the turret’s semi-basement level, facing north and west; clear evidence of the building’s defensive purpose during turbulent times. A series of beam slots suggests the turret originally incorporated a semi-basement, whilst scarring on the walls indicates a northern range once extended from the main structure.

Archaeological excavations conducted in 1995 revealed fascinating earlier phases of occupation at the site. Beneath and around the castle, archaeologists discovered remains of a 15th century stone building with clay-bonded walls, associated with medieval pottery fragments. To the east, they uncovered foundations of another large rectangular stone structure featuring a chimney in its eastern wall, which predated the castle itself. These findings suggest Ballyowen was a site of continuous occupation and importance for at least two centuries before the current fortified house was erected, painting a picture of a long-established settlement that evolved with Ireland’s changing political and social landscape.