Carrickfergus Castle
Rising straight from the basalt rock above Belfast Lough, Carrickfergus Castle is the only castle on the island of Ireland to have been in continuous use from the moment it was built — a jaw-dropping 800-year run. Besieged by the Scots, the English, the Irish and even the French, its four-storey keep still looms over the harbour like a dare.
Eight centuries of siege and survival
Built in 1177 by Anglo-Norman knight John de Courcy following his conquest of east Ulster, the castle was modified repeatedly as weapons and tactics evolved across the 13th, 16th and 17th centuries. King John besieged it in 1210, Edward Bruce in 1315, and William of Orange landed on its shores in 1690 after the Glorious Revolution.
It served as a prison during the Napoleonic Wars, a garrison in World War I, and an air-raid shelter in World War II — making it one of the most continuously repurposed military structures in the British Isles. That layered history is palpable the moment you step through the gate.
What to see inside
Climb the keep — the oldest surviving part of the structure — for sweeping views across Belfast Lough between the crenels. Down below, the banquet hall, vaults, constable's quarters and dungeon are all open, along with displays of medieval artefacts, replica armour and a collection of 17th-to-19th-century cannons still pointing seaward.
Don't miss the entrance passage's 'murder hole', through which defenders once poured boiling oil on attackers. The Visitor Information Centre inside stocks local history books and handmade crafts, and a small café is on hand for a restorative cup of tea after the climb.
Gateway to the Causeway Coast
Carrickfergus Castle sits at the very starting point of Northern Ireland's legendary Causeway Coastal Route, making it the ideal first stop before heading north toward the Giant's Causeway, Carrick-a-Rede Rope Bridge and Dunluce Castle.
The castle is just 21 minutes from George Best Belfast City Airport, so it works perfectly as a first or last impression of Northern Ireland — and it never disappoints.
Carrickfergus Castle on video
More of Carrickfergus
Discover where to stay, what to do and the best deals for your trip.
Explore Carrickfergus →
