Augustus Henry FitzRoy, 3rd Duke of Grafton (28 September 1735 – 14 March 1811), styled Earl of Euston between 1747 and 1757, was a British Whig statesman of the Georgian era.

However, he struggled to demonstrate an ability to counter increasing challenges to Britain's global dominance following the nation's victory in the Seven Years' War.

[1] In 1756, he entered Parliament as MP for Boroughbridge, a pocket borough; several months later, he switched constituencies to Bury St Edmunds, which was controlled by his family.

Chatham's illness, at the end of 1767, resulted in Grafton becoming the government's effective leader (he is credited with entering the office of prime minister in 1768), but political differences, the impact of the Corsican Crisis and the attacks of "Junius" led to his resignation in January 1770.

[3] Grafton was a strong supporter of moves to reform the militia during the Seven Years' War, and as Lord Lieutenant of Suffolk his county was one of the first to raise its quota, in two regiments on 27 April 1759.

He resigned his commission on grounds of ill-health in February 1780, and his 20-year-old son and heir, George, Earl of Euston, succeeded him as colonel of the West Suffolk Militia.

Grafton had associated with a number of liberal Anglican theologians when at Cambridge, and devoted much time to theological study and writing after leaving office as prime minister.

He was the author of: He was a sponsor of Richard Watson's Consideration of the Expediency of Revising the Liturgy and Articles of the Church of England (published in 1790), and he funded the printing of 700 copies of Griesbach's edition of the Greek New Testament in 1796.

[12] Augustus and Anne had three children: In 1764, the Duke had a very public affair with the courtesan Nancy Parsons[16] whom he kept at his townhouse and took to the opera, where they allegedly were found in flagrante delicto.

After the Duchess had become pregnant by her own lover, the Earl of Upper Ossory, she and the Duke were divorced by Act of Parliament, passed 23 March 1769.