Carlingford Castle – better known as ‘King John’s Castle’ – is a national monument set at the entrance to the scenic, medieval County Louth town. It is the ‘twin’ of Green Castle, on the other side of Carlingford Lough. Both were built around the end of the twelfth century by the Anglo-Norman knight, Hugh de Lacy, to guard the southern approaches to the Earldom of Ulster.
King John’s Castle’s royal name is believed to derive from a visit made by the Plantagenet monarch in 1210, when he is reputed to have stayed there. It is built on a rocky outcrop overlooking the harbour and offers magnificent views across the Lough to the Mourne Mountains.
The structure was developed in two phases. The western section consisted of an enclosed courtyard, rectangular entrance towers and two-storey buildings inside a walled perimeter. The eastern section, including a great hall, was added in 1261. The two wings are separated by a huge curtain wall.
The castle remained in English hands for most of the post-medieval period and has been derelict since 1689. Restoration work began in the 1950s and although the castle is closed to the public, visitors may walk around its perimeter before exploring the town’s many other historical landmarks.