Ross Castle is a fifteenth-century tower house standing on the shore of Lough Leane, about three kilometres from Killarney town. It is the best-preserved example of an O'Donoghue chieftain's castle in Ireland, and the location — surrounded by water on three sides with the lake and mountains behind — is among the most photogenic in the country.
The castle is now managed by the Office of Public Works and tours run inside the keep, showing the original furnishings, wooden floors, and the view from the battlements. The path along the lakeshore from Killarney town is a pleasant 45-minute walk through the national park. Rowing boats can be hired at the castle jetty for trips on the lake.