Sir Augustus John Foster, 1st Baronet, GCHPC (1 or 4 December 1780 – 1 August 1848) was a British diplomat and politician. Born into a notable British family, Foster served in a variety of diplomatic functions in continental Europe and the United States, interrupted by a short stint as a member of parliament. He wrote about his American experiences in Notes on the United States of America.
He enjoyed a comfortable social situation; his father was the Irish MP for Ennis and first cousin of John Foster, 1st Baron Oriel and William Foster, and his mother, Lady Elizabeth Foster, would later go on to marry William Cavendish, 5th Duke of Devonshire, was herself the daughter of Frederick Hervey, 4th Earl of Bristol. Augustus had one older brother, Frederick (1777–1853) and an elder sister Elizabeth (b. 1778), who died several days after birth, as well as two illegitimate half-siblings fathered by Devonshire. Augustus's parents separated in 1781, at which time he and his brother remained in the care of his father while his mother moved to Chatsworth House.
Ending his service in Turin and his career in the British diplomatic service in 1840, Foster began drafting his Notes on the United States of America.
Foster died in 1848 after cutting his throat at Branksea Castle; he had suffered from delirium because of poor health, and his death was ruled as the result of temporary insanity. His Notes on the United States of America would be rediscovered in a cupboard of his family's home in Northern Ireland in the 1930s, and published posthumously.
Tinkcom, Margaret Bailey (January 1951). "Caviar Along the Potomac: Sir Augustus John Foster's "Notes on the United States," 1804-1812". The William and Mary Quarterly. 8 (1): 68–107. doi:10.2307/1920734. JSTOR1920734.
^The Peerage of the British Empire as at present existing... by Edmund Lodge, Esq, Norroy King of Arms, Second Edition, Saunders and Otley,Conduit Street, 1833.