This castle is situated on the west side of the entrance to Lough Foyle, two and a half miles north-east of Moville, in the Barony of Innishowen.

It was erected upon a rock and defended by two towers which contained the chief apartments, while a third tower defended the northern end.

It is built of green fire stone, from which its present name may have been derived.

In Macator’s map, which was published in 1629, it is marked as “New Castle,” and it is still known in Irish by that name.

Hanmer’s “Chronicle” and Grace’s “Annals” state that Arx Viridis in Ultonia was thrown down in 1260, so that it is likely that the present building, which was erected by Richard de Burgo, the Red Earl of Ulster, in 1305, replaced a former fortress.

In 1332 William de Burgo, or the “Dun Earl,” owned the fortress, which he had inherited from his father, and having taken prisoner Walter, son of Sir Walter de Burgo, he starved him to death in the castle. Sir Arthur Chichester excavated one of the pillars of the dungeon in which it is supposed he was confined, and a mark was discovered that most likely had held a ring to which the prisoner was chained. The “dreary and dismal” prisons are still to be seen.

The Dun Earl was stabbed to death the next year in revenge for the murder.

The following legend is told regarding Walter de Burgo’s death. The Earl had a beautiful daughter who one day, in

crossing the sands on the shore under Benevenagh, became engulfed in quicksands, and was nearly losing her life when Sir Walter Burk’s son, who was serving in the army of O’Neill and O’Donnell, seeing her danger from the heights above rushed down and saved her from the peril.

The same year this young man was taken prisoner by the girl’s father in his war with the O’Donnells and starved to death at Greencastle. The Earl one day, during his unfortunate victim’s captivity, discovered his daughter carrying food to the prisoner, and seizing her by the hair, dragged her to the battlements and hurled her over on to the rocks below.

The fortress was for many years in possession of the O’Dohertys.

In 1555 Calvagh O’Donnell went to Scotland to raise forces with the help of Mac Calin (Gillaspick Don), and returning with them and a cannon called gonna cam, or “crooked gun,” he set to work and demolished the New Castle.

It was, however, reported as wardable in 1586. The last of the O’Dohertys to hold the fortress was knighted by Queen Elizabeth, but shortly afterwards he went into rebellion, and his estate was forfeited.

In 1610 it was granted with other property to Sir Arthur Chichester with an allowance to maintain the garrison. Two years later he asked to be allowed for horsemen at Greencastle instead of the ten warders, and in 1615 Lord Chichester was granted Greencastle for three lives by letters patent.

In 1752 it was on the Earl of Donegal’s estate.