Dublin Castle Visitor Facilities Since its foundation in 1204 Dublin Castle has been at the heart of the history and evolution of the city. Today, spanning an area of over 44,000 square meters (11 acres), the site contains 2 museums, 2 cafés, an international conference centre, 2 gardens, Government Buildings and the State Apartments which are the most important state rooms in the country. The grounds of the site are free to explore, as is the Chester Beatty Library and the Revenue Museum. Access to the State Apartments is by guided tour only and tickets may be purchased from the Apartments in the Upper Castle Yard. The State Apartments dominate the south range of the Great Courtyard.