Charles Manners, 4th Duke of Rutland

His Grace The Duke of Rutland KG PC
Rutland, oil on canvas by Joshua Reynolds, c. 1775
Lord Lieutenant of Ireland
In office 12 February 1784 – 27 October 1787
Monarch	George III
Preceded by	The Earl of Northington
Succeeded by	The Marquess of Buckingham

Charles Manners, 4th Duke of Rutland KG, PC (15 March 1754 – 24 October 1787) was a British politician and nobleman, the eldest legitimate son of John Manners, Marquess of Granby. He was styled Lord Roos from 1760 until 1770, and Marquess of Granby from 1770 until 1779.

He was educated at Eton and Trinity College, Cambridge, graduating the latter with a nobleman's MA in 1774. That year, he was elected to one of the university's seats in the House of Commons. He continued to maintain the family's substantial electoral interests, and to collect objets d'art to decorate Belvoir Castle. He pledged to redeem his father's substantial debts, but was hampered by his passion for gambling.

On 26 December 1775, he married Lady Mary Isabella Somerset (d. 1831), daughter of Charles Somerset, 4th Duke of Beaufort and a celebrated beauty, renowned for her elegance and good taste. She was one of the most prominent society hostesses. They had six children:

Later in life, he was said to have been the lover of Elizabeth Billington.

Granby entered parliament in opposition to the North Ministry and as an ally to the Rockingham Whigs. He acted only as an observer until reaching his majority, and made his maiden speech on 5 April 1775, advocating free trade with the southern American Colonies. The speech brought him thanks from his father's friend Chatham, whom he praised, and initiated a friendship with William Pitt the Younger. It much disappointed the Court, and particularly Lord Mansfield, who had thought to govern the young Granby. During the American Revolution, he followed Chatham in urging reconciliation with America, and was one of those who questioned the conduct of Admiral Keppel in March 1779. He did not follow this up, and does not seem to have spoken in Parliament afterwards, acceding to the dukedom on 29 May 1779. He was able to obtain a seat for his friend Pitt at Appleby in 1780 when Pitt failed of re-election for Cambridge University, and promised him a seat in one of the boroughs of the Rutland interest in the future. His own Parliamentary interest notwithstanding, he supported Pitt's plans for reform.