The site takes its name from John Keting of ‘Nicholestown’, who appears in records as early as 1542. By 1640, the estate had passed to Richard Keatinge, described in the Civil Survey as an ‘Irish Papist’, who owned what was then documented as ‘a Castle, the walls of a house within a bawne’; essentially a fortified tower house protected by a defensive wall.

The tower house itself, built from roughly cut limestone blocks held together with pebble-filled mortar, sits in the northwest corner of a rectangular bawn. Though time has taken its toll, the structure still reveals fascinating architectural details. The walls, measuring 2.4 metres thick, feature a defensive base-batter that extends three metres high and about 40 centimetres wide. Inside, the building measured approximately 7.15 by 7.1 metres, with traces of its original layout still visible: broken window openings in the north wall at ground and first floor levels, a wall cupboard, and the remnants of a vaulted second floor that once sprang from the east and west walls.

What makes this ruin particularly interesting are the surviving defensive features at its upper levels. The northwest corner preserves evidence of a circular bartizan, a small turret that projected from the main wall, complete with three gun-loops for firearms. This defensive structure rested on cleverly designed corbels; double supports on the north and west walls with a single chamfered corbel at the corner angle, along with gutter-stones to channel rainwater away from the walls. Though the staircase has long since collapsed, likely located at the southeast corner based on a surviving door jamb, and much of the structure lies in ruins with collapsed rubble filling the interior, these remaining elements paint a vivid picture of what was once a formidable defensive residence.