Lord Erroll married
Lady Elizabeth FitzClarence, the illegitimate daughter of King
William IV and
Dorothy Jordan, on 4 December 1820. They were the parents of four children: • Lady Ida Harriet Augusta Hay (1821–1867), who was one of the Queen Victoria's bridesmaids and who married
Charles Noel, 2nd Earl of Gainsborough. •
William Harry Hay, 19th Earl of Erroll (1823–1891), married Eliza Amelia Gore, the eldest daughter of Sir
Charles Stephen Gore (the third son, by his second wife, of the
2nd Earl of Arran) in 1848. •
Lady Agnes Georgiana Elizabeth Hay (1829–1869), who married
James Duff, 5th Earl Fife on 16 March 1846. Their son,
Alexander Duff, 1st Duke of Fife, married
Princess Louise, daughter of King
Edward VII. • Lady Alice Mary Emily Hay (1835–1881), who married Charles Edward Louis Casimir Stuart (1824–1882), nephew of fraud
John Sobieski Stuart. Lord Erroll died in London in April 1846, aged 45, and was succeeded by his eldest son,
William. The Countess of Erroll died in January 1856, aged 54. ==Recreation==