Ross Castle is a 15th-century tower house located on the edge of Lough Leane in Killarney National Park, County Kerry, Ireland. Originally built by the O'Donoghue family, it later came under the ownership of the MacCarthy Mór during the Second Desmond Rebellion. The castle surrendered to Oliver Cromwell's forces during the Irish Confederate Wars and has a rich history of military occupation. Today, it is open to the public for guided tours and is managed by the Office of Public Works. Legend has it that the spirit of O'Donoghue still watches over the castle from the depths of the lake.