Princess Augusta of Hesse-Cassel, later the Her Royal Highness the Duchess of Cambridge, (7 July 1797-6 April 1889) was the consort of Prince Adolphus, 1st Duke of Cambridge, the tenth born child and seventh son of King George III of the United Kingdom and Queen Charlotte. The longest-lived daughter-in-law of George III, she was the maternal grandmother of Queen Mary, the consort of King George V of the United Kingdom.
Her Highness Princess Augusta Wilhelmina Louisa, the third daughter of Friedrich III, Landgrave of Hesse-Cassel and his wife Caroline Polyxena, daughter of Prince Karl Willem of Nassau-Usingen, was born at Rumpenheim Castle, Cassel, Germany. Her father, Landrave Friedrich III, was the son of Princess Mary (22 February 1723-14 January 1772, the third daughter of King George II of Great Britain. In 1803, he assumed the title of Elector of Hesse-Cassel.
On 7 May at Cassel and then again on 1 June 1818, Princess Augusta married her second cousin, the Duke of Cambridge. The Duke and Duchess of Cambridge had three children:
- Prince George, 2nd Duke of Cambridge (26 March 1819-17 March 1904)
- Princess Augusta of Cambridge (19 July 1822-4 December 1916), m. Friedrich Wilhelm, Grand Duke of Mecklenberg-Sterlitz (1819-1904)
- Princess Mary Adelaide of Cambridge (27 November 1833-27 October 1897) m. Prince Francis of Teck, later 1st Duke of Teck.