Built by the O’Madden family in 1643, as proclaimed by a Latin inscription carved into its corbels (‘D : OM ME : FIERI : FECIT : 1643’), this four-storey rectangular tower is now protected as a National Monument. The castle’s Jacobean chimney stacks crown its gabled roof, whilst traces of the original slate roofing can still be spotted embedded near the western gable’s apex.

The tower’s defensive features reveal the precarious times in which it was built. The original pointed arch doorway, located near the northern end of the eastern wall, still bears traces of iron hinges that once secured a protective iron grille or yett. Musket loops flank the entrance, and the pronounced base batter would have helped deflect projectiles. Inside, a spiral staircase rises from the southeast corner, leading to floors that once held the family’s living quarters. Each level served different purposes; the ground floor housed a guardroom and main chamber, whilst the upper floors contained grander rooms with fireplaces set into the walls. Original features survive throughout, including a wall cupboard with wooden lintels on the first floor and decorated garderobe ventilators featuring intricate triskele designs.

What makes Derryhiveny particularly special is its completeness; not just the tower itself, but substantial sections of its protective bawn wall remain, including circular towers at the northeast and southwest corners. The castle showcases sophisticated 17th-century domestic arrangements, from the intramural chamber tucked into the southeast corner to the mix of plain rectangular and elegant mullioned windows that flood the interior with light. Even details like the quatrefoil window in the entrance lobby and the diagonally positioned chimney stacks demonstrate the care taken in its construction, making this one of Ireland’s finest examples of a precisely dated tower house.