Ballyhack Castle is a large five stories tall tower house and the walls survive complete to the wall walk. Built into the north-east wall of the second floor is a small chapel, thought to have been built c. 1450 by the Knights Hospitallers of St. John. One of the two great military orders founded at the beginning of the 12th century at the time of the Crusades. .

The entrance to the castle is protected externally by a machicolation and internally by a murder hole, an opening through which defenders could throw rocks or pour boiling water, hot sand or boiling oil, out on to an attackers.

Ballyhack Castle has on display assorted items of replica armour relating to the Crusades and the Normans.