They are easy to overlook: three chamfered sills from two-light windows and two chamfered window jambs, all bearing the small rectangular sinkings that once held iron bars. These are not decorative remnants placed for effect. They are the displaced bones of a building that was demolished, burned, refortified, evacuated, demolished again, occupied again, forfeited, renovated, and left once more to collapse, across a span of several centuries.

The site's first recorded structure was a castle built at Dun Loich in 1215 by Maurice FitzGerald. After the defeat of the Geraldines at the battle of Callan in 1261, the MacCarthys demolished and burned it. It was refortified within two decades, only to be abandoned again in 1280 when its garrison fled for fear of MacCarthy and the forces of Desmond, burning it behind them as they left. The ruins visible today belong to a later tower house, a tall, thick-walled fortified residence of the kind common across late medieval Ireland, associated with the O'Sullivan Mores. The Earl of Ormond is recorded as having demolished it in 1570, yet the O'Sullivans appear to have returned, since a Daniel O'Sullivan of Dunloe was representing Kerry in Parliament by 1613. The castle was forfeited in 1656 and passed to Sir William Petty, the surveyor and economist who accumulated vast Kerry landholdings during the Cromwellian settlements. By the late seventeenth century it had become the property of the O'Mahony family, and in the 1820s one of them undertook substantial renovations. The work was considerable: the east wall was largely rebuilt and set back from its original line, most of the original windows were replaced with ogee-headed openings in brickwork, and a pointed doorway was inserted into the south wall at first-floor level. A pencil sketch by the antiquarian Thomas Westropp, made in 1891, records the building in its renovated state. Traces of the timber floors and wall-shuttering from that restoration still survive inside.

The tower house stands on the northern end of an elevated ridge within the hotel grounds, overlooking a bend of the River Laune to the east. The limestone fragments on the steps below the south doorway are what remains of the earlier, pre-renovation fabric, displaced during the nineteenth-century works and left where they settled. The sinkings for bars in the sills and jambs are a small but telling detail: windows fitted with iron bars suggest a building that, at some point in its long life, still needed to take its own defence seriously.