William Cavendish-Bentinck
The duke died on 6 December 1879 at his London residence, Harcourt House. He was buried in a simple grave in a large plot at Kensal Green Cemetery in north London. As his younger brother, Henry William, had died without male issue on 31 December 1870, the title of Duke of Portland devolved upon his cousin, William Cavendish-Bentinck.