Found several US Census records that tell a bit of a story about this couple. They were a farm couple married at least 45 years. They had three children, but only one survived into adulthood - a daughter, Sarah, who became a school teacher. Couldn't find an 1870 record for them, but they appear in every other Census after that, until 1910. The records show that his parents were born in OH and hers in DE.
1880 Census - La Rue - Marion Co., OH: William H. Sprague, age 39, born in OH, "retired farmer"; wife Jane, age 33, born in OH; and daughters Nettie, age 12 - and Sarah, age 6.
1900 Census - Montgomery Twp., Marion Co., OH - William Sprague, age 59, born Oct. 1840 in OH, "day laborer"; with wife Jane, age 52, born June 1847 in OH, mother of 3 children, only 1 still living; couple married 36 years; and daughter Sarah Sprague, age 22, born Aug. 1877 in OH, "school teacher."
1910 Census - OH, Marion Co. - Montgomery Twp. - William Sprague, age 69, born in OH, retired; and wife Jane, age 63, born in OH, mother of 3 children, only 1 still living; couple married 45 years.
Note: Also found an 1850 Census record clearly belong to this Jane Clark Sprague. She was the daughter of farmer John Clark Sr., age 38, born in DE; and wife Huldah, also age 38. They had a large family, with the following nine children as of 1850 ranging in age from 19 down to 1 year: Hannah, Noah, George, Patience, John Jr., Nathan, Elizabeth, Jane, and Betsey.