She was the author of Letters on Female Character, Addressed to a Young Lady, on the Death of Her Mother (1828), an influential advice book Most likely she was born in Goochland County, Virginia, at Tuckahoe, the plantation of her parents, Thomas Mann Randolph (1741–1794) and his first wife, Ann Cary Randolph.
Her sister Judith married William Randolph"s great-grandson, Richard Randolph of Bizarre. His paternal ancestors included Pocahontas, the youngest daughter of Chief Powhatan and her English-born husband John Rolfe. They had six children: Colonel
Wilson Miles Cary (1806–1877), Archibald Cary (who married Monimia Fairfax), Jane Blair Cary, Elizabeth Randolph Cary, Mary Randolph Cary (1806–1882), and Martha Jefferson Cary (who married Gouverneur Morris Junior).
Her granddaughter was Constance Cary.
