Threave Castle is located on an island in the River Dee, close to Castle Douglas, Dumfries and Galloway.
Archibald the Grim built the castlein the 1370's for the 'Black Douglases', the Lords of Galloway, until their fall in 1455. The castle and the lordship of Galloway were controlled by Princess Margaret, daughter of King Robert III and widow of the 4th Earl.
In 1449, Threave was regained by the 8th earl, Scotland's most powerful magnate, who controlled extensive lands and numerous castles. He fortified Threave with an 'artillery house', a sophisticated defence for its time. The excessive power of the Black Douglas lords led to their overthrow by King James II in 1455, after which Threave was besieged and captured by the King's men.
It became a royal castle, and in the 16th century hereditary responsibility for Threave was given to the Lords Maxwell. It was briefly held by the English in the 1540s, but did not see serious action until the Bishops' Wars, when in 1640 a royalist garrison was besieged by a force of Covenanters.
Partially dismantled, the castle remained largely unused until given into state care in 1913.
The ruins, comprising the substantially complete tower house and the L-shaped artillery house, are today maintained by Historic Environment Scotland as a scheduled monument.