This impressive circular tower house, standing five storeys tall with an attic, dates from the 15th century and was built by the O’Dwyer family, who served as chiefs of Kilnamanagh. The castle’s limestone rubble walls, measuring nearly 11 metres in diameter and almost 3 metres thick, have weathered centuries remarkably well, surviving to gable height with traces of external render still visible on the upper floors.

The castle’s architectural evolution tells a fascinating story of changing ownership and fortunes. When surveyed in 1654, it was described as a ‘small castle wanting repaire’ surrounded by three thatched houses, thirty cabins and a water mill, with Philip O’Dwyer of Dundrum listed as proprietor. By 1665, Thomas Butler had taken possession and appears to have undertaken significant renovations; the Hearth Money Rolls show him initially charged for one hearth, increasing to three the following year, suggesting he made the castle more habitable. These alterations likely included the insertion of larger windows at hall level and the addition of a cut stone fireplace on the fourth floor, features that reflect the 17th-century taste for comfort alongside defence.

The defensive sophistication of Ballysheeda is evident in its clever design details. Four machicolations with double rows of openings protect the cardinal points, whilst the main entrance features a pointed arch doorway guarded by both a murder hole and a mural guard chamber equipped with gun loops for flanking fire. The interior spiral staircase, built into the southern wall, provides access to all levels including a garderobe at mezzanine level between the first and second floors. The windows reveal the tower’s dual nature; earlier ogee-headed openings flanked by gun loops on the lower levels give way to larger, more domestic twin-light mullioned windows with hood mouldings on the fourth floor, where the main hall was located. An unusual square cap house rises above the wall-walk, providing access to both the battlements and the attic space that once existed above the great hall.