Charles Dillon-Lee, 12th Viscount Dillon of Costello-Gallin, was born 6 November 1745 in London, Greater London, England, United Kingdom to Henry Dillon, 11th Viscount Dillon (1705-1787) and Charlotte Lee (1720-1794) and died 9 November 1813 Loughlin House, County Roscommon, Ireland of unspecified causes. He married Henrietta Maria Phipps (1757-1782) 19 August 1776 in Brussels, Belgium. He married Maria Rogier (-1833) 15 September 1787 .
He was born Charles Dillon and changed his name to Dillon-Lee in 1776 under the terms of the will of his uncle, George Lee, 3rd Earl of Lichfield. He inherited Ditchley House in Oxfordshire from his mother, Charlotte Lee, daughter of George Lee, 2nd Earl of Lichfield and as such a granddaughter of 1st Earl of Lichfield and his first wife Charlotte Fitzroy, who was an illegitimate child of Charles II. Lord Dillon inherited his title in 1787 on the death of his father Henry Dillon, 11th Viscount Dillon.
|Offspring of Charles Dillon-Lee, 12th Viscount Dillon and Henrietta Maria Phipps (1757-1782)|
|Henry Augustus Dillon-Lee, 13th Viscount Dillon (1777-1832)||28 October 1777 Brussels, Belgium||24 July 1832 London, Greater London, England, United Kingdom||Henrietta Browne (1789-1862)|
|Frances Charlotte Dillon-Lee (1780-1819)|
|Offspring of Charles Dillon-Lee, 12th Viscount Dillon and Maria Rogier (-1833)|
|Charlotte Dillon-Lee (1788-1866)|
|Henrietta Dillon-Lee (-1811)|
|James William Dillon-Lee (1792-1812)|