Ross Castle is a 15th-century tower house and keep located on the edge of Lough Leane in Killarney National Park, County Kerry, Ireland. It was originally built by the O'Donoghue family but later came under the ownership of the MacCarthy Mór during the Second Desmond Rebellion. The castle surrendered to Oliver Cromwell's Roundheads 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 former chief, O'Donoghue, leapt out of a window into the lake with his horse, table, and library, and now resides in a palace at the bottom of the lake.