Charles Sloane Cadogan, 1st Earl Cadogan (29 September 1728 – 3 April 1807) was a British peer and Whig politician.
Cadogan was the only son of Charles Cadogan, 2nd Baron Cadogan and his wife, Elizabeth, the second daughter of Sir Hans Sloane, Bart. and was educated at Magdalen College, Oxford.
From 1749–54 and again from 1755, Cadogan was a Member of Parliament for Cambridge until he inherited his father's title in 1776. He was also appointed Keeper of the Privy Purse to Prince Edward in 1756, Surveyor of the King's Gardens from 1764–69 and Master of the Mint from 1769–84. In 1800, he was elevated in the Peerage as 1st Viscount Chelsea and 1st Earl Cadogan.
In 1777 he leased 100 acres (0.40 km2) of the family estate in Chelsea to architect Henry Holland for building development. Holland built Sloane Square, Sloane Street, Cadogan Place and Hans Place.
On 30 May 1747, Cadogan married the Honourable Frances Bromley, daughter of Henry Bromley, 1st Baron Montfort. They had six children:
Cadogan's first wife died in 1768, and on 10 May 1777, he married Mary Churchill (daughter of Charles Churchill and Lady Mary Walpole, daughter of Robert Walpole) and they had four children:
Cadogan and his second wife divorced in 1796 and on his death at Santon Downham, Suffolk in 1807, his titles passed to his eldest son, Charles, by his first wife.