The castle is built on a projecting rock, surrounded by the waters of the inlet upon the north, east, and south, while on the west its entrance was guarded by drawbridge and portcullis, as well as a fosse filled with sea-water.
A modern house is attached to the old fortress, which has a rectangular tower, and a circular donjon used as a dairy in modern times.
M’Parland, writing in 1802, in his statistical survey, records that the castle was fortified with a strong tower by the grandfather of the then MacSweeny of Dunfanaghy.
There seems to be no record of the erection of the fortress, and different authorities ascribe its building to various persons. Manus Oge says Doe was erected by Nachton O’Donnell for one of his seven sons at the same time that the castles of Burt, Inch, and Ramelton were built, while M’Parland accredits a lady named Quinn with its erection, who married a M’Swine, shortly before Elizabeth came to the throne.
Dr. Allman believes it dates from about the beginning of Henry VIII.’s reign, and tradition states that Doe passed to the MacSweenys in the fifteenth century, when a peace was concluded between O’Neill and O’Donnell in 1440.
Red Hugh O’Donnell lived at Doe Castle with his foster father, Owen Oge MacSweeny, and it was while in his care that he was kidnapped at Rathmullen by Sir John Perrott in 1588.
Sir Hugh MacSwine na Oge, surnamed the Red, was one of Queen Elizabeth’s chief favourites, and a polished courtier. Very different, however, was the last of the MacSwines who occupied Doe Castle. This was Sir Miles MacSweeny of the Club, who was knighted by Oueen Elizabeth, and about whom tales of great brutality are recorded.
He was called “of the club” from his bludgeoning the better classes of his clan to death with his own hand if they offended him, while the poorer ones he consigned to a retainer called Furey and his satellites to hang from the castle walls.
A legend is told of how his beautiful daughter, Eileen, fell in love with Turlogh Oge, son of The O’Boyle, against her father’s wish. The lovers used to meet on the beach and in the woods near the castle. Her father discovered their trysts and confined her to the fortress under the care of a worthy matron. The young people were thus reduced to signalling to each other—the maiden from the battlements, and her lover from his canoe in the bay. This became known to The MacSweeny, and with two boats of armed men he waylaid the young man and a few retainers on their way back from Lackagh, and brought them prisoners to the castle.
Here he starved them to death, and as the bodies were being carried to the graveyard the fair Eileen saw and recognised her lover. She never recovered the shock and grief, and not long afterwards she was found dead on the top of one of the castle towers.