Individual Details

Never married; said to have died at about 30 years of age. I suspect she lived until sometime after the 1830 census, dying in her late 40's

Although she has often been placed with John M. Haden's 2nd wife, Mary Ann, as her mother - I believe she was instead the youngest child born his first wife. In fact, Anne, may have died when Sally was born. Mary Ann was certainly older than her age "assigned" based on her very likely sister relationship to the Flanagan brothers and confirmed by the age of the eldest female in the household of John Haden in 1810, 1820, and 1830. She had no children by her first husband and likely had no children by John Haden.

The 1830 census does show John Haden with two females age 40-50 in his household, other than his spouse. In 1810, he had also had two females age 16-26; by 1820 they were 26-45. One of these is surely Peggy who lived to appear in the 1840, 1850 (age 65) and 1860 censuses and who never married. If the other lady is Sally then her birth and death years are both wrong and increases the likelihood that her mother was the first wife.
Also a deed of gift when John Haden gave land to his then unmarried daughters, he and his wife Mary Ann are the grantors but he always refers to Peggy and Sally as HIS daughters, not ours.

Birth	Abt 1788
Death	1835

Father	John Moseley Haden (1749 - 1830)
Mother	Anne [HADEN] ( - )
Sibling	Susanna Haden (1771 - )
Sibling	William Haden (1772 - 1852)
Sibling	Nancy Haden (1780 - 1850)
Sibling	George Haden (1784 - 1829)
Sibling	Margaret Douglas "Peggy" Haden (1785 - 1865)