His eldest son and heir apparent, William Cavendish-Scott-Bentinck, Marquess of Titchfield, represented two constituencies in Parliament but died unmarried in 1824, 15 years before his father.

The fifth Duke is remembered as a capable architect and engineer but eccentric, who excavated an underground art gallery and library under his estate at Welbeck Abbey.

His eldest son, William Cavendish-Bentinck, 7th Duke of Portland, was also a Conservative politician and served as a Junior Lord of the Treasury from 1927 to 1929 and in 1932.

[1] The great estates which had been entailed with the dukedom for generations, including Welbeck Abbey, were separated from the title by the sixth Duke, who broke the entail and created a trust which ultimately ensured that his granddaughter Lady Anne Cavendish-Bentinck inherited the ducal wealth on the death of her father, the seventh duke.

He was childless and was succeeded by his younger brother, Victor Cavendish-Bentinck, 9th Duke of Portland, a diplomat who had served as British Ambassador to Poland.

[1] The ninth Duke was succeeded in his other peerages by his sixth cousin, Henry Bentinck, 11th Earl of Portland.

As of 2017[update], the titles are held by his only son, the twelfth Earl, born in Australia, who is also Count Bentinck of the Holy Roman Empire.

Lord Frederick Cavendish-Bentinck, fourth son of the third Duke, was a major-general in the army and a Tory MP.

Cecilia Bowes-Lyon, Countess of Strathmore and Kinghorne, maternal grandmother of Elizabeth II, was a Cavendish-Bentinck before marriage.

Welbeck Abbey and its many acres continued in the senior branch of the family (becoming Cavendish-Bentinck) through the ancestry of a daughter of the 7th Duke.

The traditional burial place of the Dukes of Portland at Welbeck Abbey was the churchyard of St Winifred's Church in the nearby village of Holbeck.

The heir apparent is the present holder's eldest son, William Jack Henry Bentinck, Viscount Woodstock (born 1984).

The heir apparent is the present holder's eldest son, William Jack Henry Bentinck (born 1984), whose courtesy title is Viscount Woodstock.