Built in 1603, as evidenced by an inscribed date within a decorative scroll on the third-floor fireplace, this four-storey limestone structure with its attic level rises impressively from the hummocky field that surrounds it. The Civil Survey of 1654-6 records two ‘decayed castles’ in the parish of Knockgraffon, both with walls still standing, and notes that the property had multiple owners including James, Earl of Ormond, and various Irish Catholic families such as Richard Butler of Ballynakill and Richard Bourke of Knockgraffon.

The tower house, measuring approximately 9 metres by 11.5 metres with walls over 2 metres thick, showcases the defensive architecture typical of its era. Its limestone rubble construction features well-cut quoins; the lower ones crafted from sandstone, the upper from limestone; and retains much of its original external render. The building bristles with circular and horizontal gun-loops, most visible only from the outside, whilst angle machicolations at the north and south corners and a box machicolation above the main entrance speak to its defensive purpose. Entry is through a pointed doorway on the southeast wall, complete with yett-holes for securing a defensive iron gate, leading into a small lobby area that once likely featured a murder-hole overhead.

Inside, the castle reveals layers of history through its architectural modifications. Though the original wooden floors have long since vanished, the tower’s vertical progression remains clear through its mural staircase that winds up the southwest wall. Each floor served distinct purposes: the first floor contained living quarters with an ogee-headed window, fireplace, and garderobe chamber tucked into the eastern angle; the second and third floors provided additional accommodation with their own fireplaces and mural chambers. Sometime in the 18th century, the tower underwent significant alterations when many windows were enlarged and broken out, and well-preserved internal plaster was added, transforming this military structure into a more comfortable residence. An 18th-century sketch suggests a tall gabled building once adjoined the southwest face, though only the tower house remains today, standing as a testament to centuries of Irish history.