Originally developed as a coastal defence fortification in the 16th century to protect upper Cork Harbour and port, there is now an observatory, visitor centre and restaurant.
In the late 16th century, the citizens of Cork appealed to Queen Elizabeth I to construct a fort at Blackrock to “repel pirates and other invaders”. In 1582 a fortification was built on the site, and later around 1600, a round tower was constructed to safeguard against pirates “carrying away” vessels entering the harbour.
Throughout this period, the castle was used by Cork Corporation for banquets and “convivial gatherings” – some associated with the custom of “throwing the dart”. This custom, dating to at least the 18th century, was held every three years in August, and involved a dart (an arrow about four feet long) being thrown by the Mayor from a boat, to indicate the Corporation’s jurisdiction over the harbour.
Following a banquet, the castle was destroyed by fire in 1827. The rebuilding began at the direction of Mayor Thomas Dunscombe in 1828 and was completed in March 1829. The neo-gothic complex of buildings around a courtyard is essentially what remains today.
The castle entered private hands and for a time in the 20th century was used as a private residence, offices, rowing club headquarters, and restaurant.
Opened in 2007, the Blackrock Observatory the “Cosmos at the Castle” project was intended to create a “centre for scientific research, outreach and communication”.The castle’s observatory houses an interactive astronomy center which is open to the public, and has exhibits including a “tour of the universe”.
Many ACET students have visited and taken tours at Blackrock Castle.