The O’Kelly family, prominent in the region, likely built their tower house here in the late 15th century, taking advantage of what the place name Athleague suggests was an ancient fording point. The castle’s location made it a coveted prize during the turbulent years of medieval Ireland, and its fortifications included what historical records describe as a bawn, a defensive wall that enclosed the tower house and provided additional protection for livestock and inhabitants during times of conflict.

The castle’s military significance became evident during a series of dramatic sieges and counter-sieges in the late 1400s. In 1487, Ulick Mac William Burke destroyed the bawn at nearby Athliag Maenagan during one of the many territorial disputes that characterised the period. The main castle faced its own trials in 1499, when Garrett Mór Fitzgerald, serving as both Justiciar and Earl of Kildare, captured it from the O’Kellys. William Burke swiftly recaptured the fortress and, in a gesture that speaks to the complex web of alliances in medieval Ireland, returned it to the sons of William Kelly. By the 1570s, however, the castle had passed into English hands; Sir Thomas le Strange leased it from Queen Elizabeth I, though by 1596 the structure lay in ruins.

The site didn’t remain abandoned for long. By 1640, the Earl of Clanrickard had acquired Athleague, and archaeological evidence suggests that either he or one of his predecessors constructed a fortified house on the ruins of the old O’Kelly castle sometime before that date. Today, nothing remains of the original medieval tower house that once guarded this river crossing, though the site continues to tell the story of how control over strategic waterways shaped the political landscape of Connacht. The location, marked as RO041-048005 in archaeological surveys, serves as a reminder of the layers of history that lie beneath the Irish countryside, where centuries of conflict, alliance, and architectural evolution have left their mark on the landscape.