Lady Charlotte Anne Thynne was born at the Thynne family seat of Longleat in Wiltshire on 10 April 1811. She was the youngest daughter and tenth child of Thomas Thynne, 2nd Marquess of Bath and the Hon. Isabella Elizabeth Byng, daughter of George Byng, 4th Viscount Torrington. Her siblings included Henry Thynne, 3rd Marquess of Bath; Elizabeth Campbell, Countess Cawdor and Louisa Lascelles, Countess of Harewood.
