Green Castle

This royal castle was built in the mid-13th century by the Anglo Norman Hugh de Lacy to defend the southern approaches to the Earldom of Ulster. On a rocky height beside Carlingford Lough, it commanded the ferry link with Carlingford and defended sea and land communications, from Drogheda and Carlingford to Dundrum and Downpatrick.

The castle is a four-sided enclosure with D-shaped towers at the corners, much of it reduced to ground level, and a large rectangular keep or hall in the middle. The hall was originally entered by a first-floor door but the entrance was later changed to the ground floor and many other alterations were made.

The impressive ditch surrounding the curtain wall was hewn out of the rock to a depth of nearly 12 feet and the stone used to build the curtain wall. A section has been excavated on this, the east side, and left open to view.