Cahir Castle , County Tipperary
Sited on a rock Island in the River Suir , this predominantly 15th century defensive castle is the largest of its period in Ireland. It is built on the site of a 3rd century fort , and King Brian Boru had a residence here during the 10th century. Despite its many defences , the castle was taken in 1599 by the Earl of Essex after a 10-day siege and by Cromwell in 1650.
The castle is a real hidden gem which makes it worth a visit on your tours of Ireland.