William Lennox Lascelles FitzGerald-de Ros, 23rd Baron de Ros of Helmsley, was born 1 September 1797 in Thames Ditton, Surrey, England, United Kingdom to Henry FitzGerald (1761-1829) and Charlotte Boyle-Walsingham, 21st Baroness de Ros (1769-1831) and died 6 January 1874 Old Court, Strangford, County Down, Ireland of unspecified causes. He married Georgiana Lennox (1795-1891) 7 June 1824 in London, England, United Kingdom.
|Offspring of William Lennox Lascelles FitzGerald-de Ros, 23rd Baron de Ros and Georgiana Lennox (1795-1891)|
|Frances Charlotte FitzGerald-de Ros (1825-1851)|
|Dudley Charles FitzGerald-de Ros, 24th Baron de Ros (1827-1907)|
|Blanche Arthur Georgina FitzGerald-de Ros (1832-1910)|