It was situated on the Armagh bank of the River Blackwater, it was armed with 150 men under the command of Sir Toby Caulfield, whose descendants took the name Charlemont from the place.

[1] The Stronghold of Charlemont proved to be of great strategic importance in the Irish Confederate Wars in the 1640s, as it was one of only a handful of modern fortresses to be found in Ireland at that time.

It was captured by the forces of Felim O'Neill in 1641 and the Ulster army of the Irish Confederates managed to hold on to the fort throughout the 1640s.

O'Neill's forces were able to capture the fort by exploiting his landed status, calling on Lord Caulfield for dinner.

[1] Governors of Charlemont included: On 30 July 1920 a group of around forty armed from the Irish Republican Army men seized the fort, which was being occupied by a caretaker, and burned it down.