William George Spencer Cavendish, 6th Duke of Devonshire (1790 - 1858), was known as the "Bachelor Duke". In 1811, at the age of 21, he inherited eight stately homes and 200,000 acres (809 km²) of land. He went on to improve his houses and gardens (including the rebuilding of the village of Edensor) and traveled extensively.

He was Lord Chamberlain to King William IV and a close friend of Czar Nicholas I of Russia. Among his friends were also Antonio Canova, Charles Dickens, and his head gardener, Sir Joseph Paxton.

The 6th Duke had two sisters, both of whom married well. One of his nieces Lady Blanche Howard married his heir presumptive, the 2nd Earl of Burlington (grandson of Lord George Cavendish, cr. 1st Earl of Burlington, yr brother of the 5th Duke), and thus their children were also great-grandchildren of the 5th Duke. Unfortunately, Lady Burlington died young. Her widower did not remarry, even when he succeeded the 6th Duke in 1858.

Much of the 6th Duke's private correspondence, including letters to his mistresses (one of whom he installed nearby), was destroyed by his Victorian relatives. The Duke is said to have wanted to marry The Princess Mary, a daughter of George III, but she preferred to marry her Royal cousin the 2nd Duke of Gloucester (son of her uncle by his wife, who was born an illegitimate commoner).