The daughter of Sir Henry Cavendish, second baronet; in 1783 she became the second wife of Arthur Annesley, first Earl of Mountnorris. She was the mother of Lady Frances Webster.

REFERENCES TO Sarah Annesley, countess of Mountnorris [née Cavendish]:

Lady Caroline Lamb to Lady Melbourne, [June?] 1815 in In Whig Society 1775-1818: Compiled from the hitherto unpublished Correspondence of Elizabeth, Viscountess Melbourne, and Emily Lamb, Countess Cowper, afterwards Viscountess Palmerston (London: Hodder and Stoughton LTD., 1921)