Susan Lyon, née Cochrane, Countess of Strathmore and Kinghorne ( before 1710 – 23 June 1754) was the daughter of John Cochrane, 4th Earl of Dundonald, husband of Charles Lyon, 6th Earl of Strathmore and Kinghorne and "Scotland's fairest daughter", to quote a chronicler of the time. She married Charles Lyon, 6th Earl of Strathmore and Kinghorne, but he was killed in an unfortunate brawl at Forfar by Carnegie of Finhavon in May 1728, leaving no heir. The resulting trial is famous for establishing in Scots law the "not guilty" verdict. Later the Countess married her servant and was shunned by her family until she died in Paris leaving a daughter who was left penniless by her rich relatives.
Lady Susanna Cochrane was born the second daughter of John Cochrane, 4th Earl of Dundonald, with "all that rank and wealth and beauty could give were hers by birth". Her mother was Anne Murry daughter of Charles Murray, 1st Earl of Dunmore. Her paternal grandmother was Lady Susanna Hamilton, daughter of the Duke of Hamilton and granddaughter of the Duchess of Hamilton who had had a claim to the Scottish throne (although this was dependent upon the failure of the House of Stewart).