On 21 July 1784, Wyndham married Frances Mary Harford, the illegitimate daughter of
Frederick Calvert, 6th Baron Baltimore and Hester Whelan. They had five children: •
George Francis Wyndham (1786–1845), succeeded his uncle as
4th Earl of Egremont • Frances Wyndham (bapt. 18 February 1789 – 1870), married firstly in 1809 William Miller, of Ozleworth Park, co. Gloucester, and married secondly in 1847 as his second wife Augustin Denis Pinon-Duclos, 2nd Vicomte de Valmer • Laura Wyndham (bapt. 6 May 1790 – 6 September 1833), married 1812 Rev. Charles Boultbee, and had issue • Julia Wyndham (11 January 1793 – February 1811), died young; buried at Petworth • William Wyndham (bapt. 20 July 1794 – 5 October 1795), died in infancy in Italy She died 22 March 1822 in Florence. widow of Count Ignacy Spytecki (), Chamberlain of the
King of Poland, from whom she inherited lands in
Kydantsi,
Ternopil,
Kingdom of Galicia and Lodomeria (now Ukraine). • Julia Karolina Maria Wyndham (1 March 1807 – 18 June 1893), baptised Catholic in April 1807 in Vienna and Anglican in
Heydon, Essex, in 1811; married (under the name Julia Wyndham Spytecka) in 1830 Richard Hasler, of
Aldingbourne House, Sussex • Col. Arthur Wyndham (19 April 1813 – 29 March 1874), served with the Madras Infantry in India and China. Married in 1856 Emily Frances Ballantine Spedding. • Emily Frances Wyndham (5 April 1822 – 1 June 1899), born in
Königsberg; married in 1848 James Dykes Spedding (died 1851); married secondly in 1859 Maj. George Charles Degen Lewis (1795–1871) ==References==