Marriage and children
Richmond married Lady Sarah Cadogan (1705–1751), daughter of William Cadogan, 1st Earl Cadogan, on 4 December 1719 at The Hague, Netherlands. They had twelve children, including a firstborn son, Charles, who died in infancy, and a surviving son, also named Charles, who inherited the titles. The twelve are:
Lady Georgiana Carolina Lennox (27 March 1723 – 24 July 1774), married Henry Fox, 1st Baron Holland, and had issue.
Lord Charles Lennox (3 September 1724 – 1724), Earl of March.
Lady Louisa Margaret Lennox (15 November 1725 – May 1728).
Lady Anne Lennox (27 May 1726 – 1727).
Lord Charles Lennox (9 September 1730 – November 1730), Earl of March.
Lady Emilia Mary Lennox (6 October 1731 – 27 March 1814), married first James FitzGerald, 1st Duke of Leinster, and had issue; and secondly William Ogilvie and had issue.
Charles Lennox, 3rd Duke of Richmond (22 February 1735 – 29 December 1806).
Lord George Lennox (29 November 1737 – 25 March 1805), General, father of Charles Lennox, 4th Duke of Richmond.
Lady Margaret Lennox (16 November 1739 – 10 January 1741).
Lady Louisa Augusta Lennox (24 November 1743 – 1821), married Thomas Connolly but had no issue.
Lady Sarah Lennox (14 February 1745 – August 1826), married first Sir Charles Bunbury, 6th Baronet, and had issue (although not by her husband, but by Lord William Gordon); and secondly George Napier by whom she had issue.
Lady Cecilia Lennox (28 February 1750 – 21 November 1769), unmarried.
Richmond's interment was at Chichester Cathedral. His wife Sarah survived him by only one year.