Cousland Castle is a 13th C. tower the remains of which lie just to the south of the Midlothian village of Cousland. Only part of its vaulted basement storey is still extant, the tower having been destroyed by Edward Seymour, Duke of Somerset, following the Battle of Pinkie in 1547.
It was most likely built during the reign of William the Lion and came into the possession of the Sinclair family around 1215. It passed through the hands of the MacGills before ending up the property of the Dalrymple Earls of Stair.
In 1567, the ruins of Cousland was the site of the encampment of the Protestant Lords, under the Earl of Morton, before their stand-off with Mary, Queen of Scots, at Carberry Hill. It was to this camp that Mary was taken following her surrender.