Myrton Castle (pronounced "Merton" and sometimes spelled Myretoun) is located in the Dumfries and Galloway about one mile from Port William in the Mochrum District of Wigtownshire. The castle sits on a hill overlooking the White Loch of Myrton near Monreity Mains near Luce Bay. Like Druchtag, the castle sits on a motte, or man-made hill. Myrton Castle was built about 1500 or earlier, and may have replaced a wooden fortress dating back to the 1100's. It was originally built as a tower house and additions were added into the 1600's and 1700's. It rises four stories and a garret and has a parapet. The rooms are connected by a circular stone stairway.  Moats filled with water surrounded part of the castle. Prior to its abandonment in 1790, the castle complex included about a dozen buildings including a small chapel, stables, coach sheds, barns, bakeries and kitchens.

The early history of Myretoun Castle and the Barony of Myretoun were associated with the McCullochs of Myretoun and later the Maxwells of Moneity. Both families were Baronets of Nova Scotia. In 1504, James IV granted a charter to Sir Alexander McCulloch and elevated Myreton Castle, its principal seat, into a Burgh of Barony. A fovorite of the king, Sir Alexander was the king's falconer. King James IV often stopped by Myretoun Castle to stay on his travels. The king also appointed Sir Alexander as Sheriff of Wigtown from 1498 to 1501. In 1580, King James VI (later James I of England) passed the Barony to William McCulloch, the son and heir of Simon McCulloch. On April 24, 1622, James VI re-granted the barony to doctor John McCulloch. The last McCulloch to occupy Myretoun Castle was Sir Godfrey McCulloch, who was convicted of murder and guillotined. Before his execution he sold his barony to Sir William Maxwell of Monreith.

Source

The Descendants of Captain John McCollough (1770-1847) And Anna Elizabeth Spangler (1779-1858) - 2006, Mark and Curtis McCollough