Dún na Séad Castle was built in 1215 by an Anglo Norman, Sleynie. It become the chief residence of the O’Driscoll clan for 300 years and was the centre of administration for their trading and piratical activities. In 1631 the castle narrowly escaped attack by a band of Algerian pirates, who landed in Baltimore and took 107 captives to a life of slavery in North Africa. In 1649 it became a garrison for Cromwellian troops, after which it declined into a state of ruin.

In 1997 the extensive task of renovation began which restored the castle to its former splendour. A visit includes a stroll through the Great Hall on the first floor, which contains furnishings, tapestries and historical descriptions of the 800 year history. View archaeological details and finds and climb to the battlements to view Baltimore Harbour and the Islands.