This castle is situated in the Barony of Lower Glenarm, a little more than twenty-five miles north of Belfast, in the County Antrim, where the Glenarm rivulet enters the bay.

The original stronghold was erected by the Byset family about the middle of the thirteenth century, and came into the MacDonnell family through the marriage of Margery Bisset.

The castle stood on the southern side of the river at the head of the street which leads from the barbican, and on the opposite bank from the present building.

In 1278 an inquisition was held after the death of two John Bysets to determine if the Earl of Ulster was right in making the fortress over to the Bishop of Connor as ecclesiastical property, and it was decided that the Bysets had not held the castle from the church.

Captain Pers and Malbie placed Randal Oge in possession of the stronghold in 1568, but the same year his ward surrendered it.

In 1597 it is reported James and Randal M’Donnell “broke” the castle, and it does not appear to have been afterwards rebuilt, although the ruins were standing for many years.

Sir Randal MacDonnell was granted the estate in 1603, and began to erect the present castle.

Sir Awla M’Awla petitioned against his possession of Glenarm in 1610, but apparently without effect.

Sir Randal greatly enlarged the dwelling in 1636, and the following inscription was placed over the entrance:—

“With the leave of God this castle was built by Sir Randal McDonnel, Knight, Erle of Antrim, having to wife Dame Aellis O’Neill, in the year of our Lord God, 1636. Deus est adjutor meus.”

Shortly after this the family made Glenarm their chief place of residence instead of Dunluce Castle.

The fortress is approached by a barbican standing on the northern side of the bridge, while an avenue of limes leads to the hall door. The building is flanked by towers crowned with cupolas and vanes, and the gables are decorated with heraldic devices.

An embattled wall guards the terrace on the river side.

The hall, which is also used as a billiard-room, is especially handsome, while the dining-room and drawing-room are also fine apartments.

Some treasure chests said to have belonged to the Spanish Armada are preserved in the castle, but a doubt has been thrown upon their being of such a date.

During the rebellion of 1798, the castle was used as the headquarters of the Yeomanry. The rebels had decided to attack it on the 8th of June, and the wives of the Yeomen, whom they had captured, were to be placed in front of the insurgents in their advance.

This diabolical plan was frustrated on the very morning of the intended attack by news of the defeat at Antrim, whereupon the camp was broken up.

Glenarm is the seat of the Earl of Antrim, the present representative being the sixth peer.