Cavendish-Bentinck

Cavendish-Bentinck is a surname associated with the Dukes of Portland and their descendants. Bentinck is a Dutch surname brought to England by William Bentinck, an advisor to William III of England. Cavendish was added to the family name by Bentinck's great-grandson the 3rd Duke of Portland, who married in 1766 Lady Dorothy Cavendish, daughter of the 4th Duke of Devonshire. By a family arrangement, she was the heiress to estates which had previously belonged to the defunct Newcastle branch of the Cavendish family, including Welbeck Abbey, which became the principal seat of the Dukes of Portland. Following the death of the 9th Duke in 1990, the family name became extinct.

People with this surname include:

...
Wikipedia