In 1524 William Cuninghame inherited the lands from his father John and both parts were sold to John Edmeston, Minister of Cardross, whose son John sold them to Jonathan Anderson, a Glasgow Merchant. William Henry Ralston, a cadet of the Ralstons of that Ilk purchased them in 1790 from John, son of Jonathan Edmeston. A nephew, Alexander MacDougal Ralston inherited in 1833. Margaret Fullarton was the wife of Alexander McDougall Ralston. They were buried in Dreghorn parish churchyard. The three sections of Peirstoun were known as Pierstoun-Barclay, Pierstoun-Blair and Pierstoun-Cunninghame. This latter portion is thought to have contained Warrickhill itself.