Only Dunsoghly has retained its original medieval trussed roof.This has survived because the castle, built around 1450 by Sir Rowland Plunkett, Chief Justice of the King's Bench, was continuously occupied until the 1870s by descendants of the same family, despite being cramped and uncomfortable by post-medieval standards. The lofty four-storey tower of the castle has tapering corner turrets rising above the parapet.
The stair occupies the north-east turret, while the others contain vaulted rooms, one of which ñ the topmost chamber of the south-west turret ñ was used as a prison and is only accessible through an opening in the vault above it. The roof, which has served as a model for restorations at Bunratty Castle and Rothe House, Kilkenny, is arch-braced with four oak principals; on each collar-beam stands a king-post supporting a purlin and cross-pieces below the ridge. The rafters are laid flat rather than on edge as in modern roofs and the framework covered with split laths.
There is a small chapel to the south bearing the year 1573 over the door, the Instruments of the Passion and the initials of John Plunkett and his wife Genet Sarsfield. On the west and south are remains of earthwork defences put up during the warfare of the 1670s.
The castle had been surrendered to Rory Maguire on the evening of Christmas Eve 1641 by Lady Hume on condition of safe conduct for the local Protestant settlers who had sought refuge with her. However, the "rebels having stripped the inhabitants, except Lady Hume, of all their clothes, imprisoned them in the vaults and cellars" of the castle. The men were bound hand and foot and "thrown into the courtyard where they lay all night". The next day (Christmas Day) the Maguires massacred all sixteen men and sixty-nine women and children, sparing only the Humes. They then pillaged and burnt the castle, which has remained a ruin to this day.
The Maguires would have had difficulty investing the castle by force as it was well protected. When the Commissioners visited the place in 1622 they found it had "a bawne of stone and lime 99 feet long, 9 feet broad, 10 feet high, with 4 flankers. There is also within the bawne a strong castle 54 feet long, 19 feet broad, 3 storeys high, covered with thatch." Of this, the stronghouse survives to almost full height, while the bawn wall and its rectangular flankers are ruined except for the north-east side. The stronghouse, of two storeys with attics, has a typically Scottish T-shaped plan with a square wing pro jecting from the centre of the south side containing the entrance and a former scale-and-platt timber stair. The hall and parlour lay on the first floor, while the attics above contained the bedrooms, approached by a spiral stair in a Scottish-style quarter-round turret projection. The ground floor consists of a large barrel-vaulted chamber used as the kitchen and store- it has a huge fireplace and cooking recesses, but there are no windows, so light must have been provided by the fire and hanging lanterns.
A ten-year programme of repair followed the acquisition of the castle by the Department of Environment in 1974. Excavation revealed that the bawn was divided up by cobbled paths suggesting the use of this area as a garden. In 1988 formal beds were created within these paths using plants known in Ireland during the seventeenth century.
The ruins of Dunluce Castle have a desolate, awe-inspiring grandeur as they rise dramatically from a precipitous basaltic rock standing over a hundred-feet sheer above the wild and chill northern sea. Separated from the mainland by a deep chasm crossed only by a narrow bridge and penetrated below by a long cave, this precarious rocky outcrop occupied a position of great strategic importance that was fought over for centuries, eventually becoming, in the sixteenth century, the principal stronghold of the McDonnells, "Lords of the Isles" and rulers of far-flung territories along the western Scottish seaboard.
Dunluce was probably used as a fort during Early Christian times and a souterrain from this period survives beneath the present ruins. Although the site is mentioned as part of the de Burgo manor of Dunseverick in the early fourteenth century, the earliest features of the castle are two large drum towers about 9 metres in diameter on the eastern side, both relics of a stronghold built here by the McQuillans after they became lords of the district (known as "the Route"), in the late fourteenth century.
Most of the castle ruins standing today were built by Sorley Boy McDonnell (1505-89) and his descendants, the first and second Earls of Antrim. The castle had been seized by Sorley Boy in 1558 after the death of his brother Colla, who had married the daughter of the McQuillan chief in 1544. Although twice evicted, first in 1565 by Shane O'Neill and again in 1584 by the Lord Deputy, Sir John Perrott, Sorley Boy managed, with the aid of artillery, to resume occupation after a short period and was officially appointed Constable of Dunluce by the Queen in 1586.
Repairs to the damage caused by the 1584 siege to the castle's landward side were probably still in progress when Sorley Boy died in 1589. New work carried out at this time included the turretted gatehouse in the Scottish manner and cannon ports in the curtain wall evidently made to accommodate cannons taken from the nearby wreck of the Spanish Armada ship the Girona in 1588. The north-facing Italianate loggia behind the south curtain probably dates to the 1560s; it is a most unusual feature but can be paralleled at a number of Scottish castles. This loggia was blocked by a three-storey gabled house with bay windows, a large projecting stair-well and a great hall 28 by 10 metres. It was built in 1636 for Lady Catherine, wife of Randal MacDonnell, the second earl of Antrim (1609-82), and, from an inventory dating from the period, is known to have been furnished magnificently.
Lady Catherine was also possibly responsible for part of the mainland court, believed to have been built to replace the lower yard after some of its domestic ranges, including the kitchens, fell into the sea carrying with them most of the servants in 1639. After the Royalist second Earl was arrested at Dunluce in 1642 the family ceased to reside at Dunluce Castle, which gradually fell into decay, though it remained the property of the Earls of Antrim until 1928 when it was transferred to the State for preservation.