Through his daughter Henrietta, he was ancestor to Clementine Hozier (the wife of Winston Churchill) and to the Mitford sisters.

[3] Henry Augustus's mother was the daughter of Constantine John Phipps, 1st Baron Mulgrave.

[5] In 1787 his father remarried to Marie Rogier of Mechelen,[6] who was an actress in Brussels and had been his mistress before he married Henry's mother.

[9] In 1799, aged 22, he contested and won a by-election caused by the death of Richard Hopkins MP for Harwich Borough, County Essex.

The marriage took place at Browne ancestral Castle MacGarrett near Claremorris, County Mayo, Ireland.

Henry Augustus and Henrietta had ten children: Dillon-Lee's regiment was ordered to Halifax, Nova Scotia, Canada, to where he also took his wife and where his eldest child was born in 1807.

[12] On 9 November 1813 his father died at Loughglinn House, County Roscommon, and was buried in the Dillon Vault at Ballyhaunis.

His widow died thirty years later at the Hotel Windsor, Paris, 18 March 1862, aged 73.