His eldest son, the second Earl, fought as a Royalist in the Civil War and was created Marquess of Antrim in the Peerage of Ireland in 1645.

However, in 1785 King George III created him Viscount Dunluce and Earl of Antrim in the Peerage of Ireland, with remainder to his daughters in order of seniority and the heirs male of their bodies.

[1] In 1789 he was further honoured when he was made Marquess of Antrim in the Peerage of Ireland, with normal remainder to the heirs male of his body.

He was succeeded in the viscountcy and earldom of 1785 according to the special remainders by his eldest daughter Anne Catherine, the second holder of the titles.

Their daughter Lady Frances Anne Vane-Tempest married Charles William Vane, 3rd Marquess of Londonderry, and was the great-grandmother of Prime Minister Sir Winston Churchill.

The heir apparent is the son of the present Earl, Alexander David Somerled McDonnell, Viscount Dunluce (born 2006).