Sarah was the daughter of Samuel Beardsley (1638-1705), a member of Stratford society, and his wife Abigail Clarke. H. F. Johnston, editor of Wm. Beardsley of Stratford Connecticut and His Descendants, says that Sarah's husband was John Barnum.
The Abridged Compendium of American Genealogy says that Sarah Beardsley (b. 1688) m. Thomas Barnum (1663-1730); (son of Thomas).
She is named in her father's will as Sarah Barnum. She is listed as a patient in the medical records of John Winthrop, Jr., which also record her father and husband.
Stratford was formerly known as Cupheag Plantation and prior to that Pequonnocke.