The structure is long and rectangular, far too sprawling and domestic in its proportions to resemble the compact tower houses that pepper the Irish midlands. Its ground plan, measuring roughly 20.6 metres by 9.6 metres externally, points instead to a 17th-century house, a more modest, residential kind of building whose designation as a castle probably owed more to local memory and social aspiration than to any serious military function.

By the time the Civil Survey was compiled between 1654 and 1656, surveyors were already recording merely the stump of an old castle at the townland then known as Knockanecanvoy. In 1640 the land had been held by Thomas, Lord Baron of Cahir, described in the survey's blunt administrative shorthand as an Irish Papist, a notation that placed him among the Catholic landowners whose titles and properties were under increasing pressure in the decades before and after the Cromwellian settlement. The building itself is constructed from limestone and sandstone rubble, roughly coursed, and sits just off the flat summit of its hill, oriented on an east-west axis. The western end is divided by an internal crossing-wall, creating a small chamber now choked with rubble and nettles, while the eastern end has surrendered entirely to brambles.

The walls survive to a maximum height of just 1.7 metres at the western end of the north wall, and there is no clearly identifiable original entrance, though a dip roughly 1.6 metres wide in the grassed-over southern wall may mark where one once stood. There is no base-batter, the thickening at the foot of a wall that was a common defensive feature of genuine tower houses, which further supports the reading of this as a domestic building rather than a fortification. What remains is largely grass-covered and deeply embedded in the hillside vegetation, more a raised outline in the ground than anything approaching an upstanding ruin.