1850 census of Sangerville, Piscataquis, Maine: Sarah Farnham, age 8, born in Maine, listed with parents, Jotham, 47 & Mary A, 36 and siblings, Ellen, 7, William, 6, Mary, 4 and Julian (female), 2.
1870 census of Sangerville, Piscataquis, Maine p15: Sarah Bennett, age 28, born in Maine, listed with husband, John, 39 and children, Ernest, 7 and Edith M, 5 (and possibly others).
1880 census of Sangerville, Piscataquis, Maine p30C: [discrepancy in death] Sarah A Bennet, age 38, she & parents born in Maine, listed with husband, John L, 49 and children: Earnest E, 17, Edith M, 15, Robert P, 6, Sarah A, 4 and Susan E, also 4.
According to the IGI, Pedigree Resource File and Ancestral File at familysearch.org, Sarah Augusta Farnham was born 25 Jan 1842 in Sangerville, Piscataquis, Maine to Jotham Farnham & Mary Ann Eveleth and married John S Bennett (who was born 1840 [discrepancy]) on 3 Mar 1861 in Sangerville and died 17 Dec 1883.
Maine Marriages, 1771-1907: Sarah A Farnham married John L Bennett on 27 Apr 1861 in Sangerville, Piscataquis, Maine.