On 30 October 1807, Lady Sarah married John George Monson, 4th Baron Monson of Burton, becoming Lady Monson. Her husband died in 1809, aged 24.Mosley, Charles, editor. Burke's Peerage, Baronetage & Knightage, 107th edition, 3 volumes. Wilmington, Delaware, U.S.A.: Burke's Peerage (Genealogical Books) Ltd, 2003. Page 2740. They had one child, Frederick John Monson, 5th Baron Monson of Burton, who married Theodosia Blacker in 1832, but died childless in 1841.
