Today, only two weathered wall fragments break the surface of the lake, marking what was once a formidable tower house on a small island near the northern shore. The castle’s decline began early; by the mid-1600s, contemporary records were already describing it as ‘the stumpe of a castle’, with ownership attributed to John Grace of Ballylensy, noted in historical documents as an ‘Irish Papist’.

The island itself, measuring roughly 20 metres north to south and 18 metres east to west, tells its own intriguing story. Encircled by the ruins of a narrow drystone wall that once stood up to a metre high, with a landing point on the northern side, the island may not be entirely natural. Archaeological evidence suggests it could have been artificially constructed, possibly originating as a crannóg; one of those distinctive fortified lake dwellings that dotted Ireland’s waterways during the medieval period.

What survives of the tower house is modest but revealing. The northeast corner still stands to just over four metres, built from roughly coursed limestone and sandstone rubble. Architectural details remain visible despite centuries of decay: a pointed doorway in the north wall once provided ground floor access, with a straight staircase rising westward; a garderobe chute and internal partition wall can still be traced within the corner angle; and stone springers on the north wall’s inner face indicate where a barrel vault once spanned the ground floor from east to west. These fragments, though sparse, paint a picture of a once-substantial fortification that commanded this watery corner of North Tipperary.