Children of Obadiah Sprague and 2nd wife Anna (Mallard) Goddard: Nathaniel, b. 26 Sep 1817; rem. to Taunton, Mass.
↑ No birth record has been found and the posting relies on the Sprague Genealogy as cited. The only definite record of Nathaniel is his marriage to Miranda (Harrison) Arnold which lists his parents. This would appear to confirm his existence as a child of these parents. Presumably, then, the 1870 census with Miranda is him despite the marginal birth information.
In 1880, a Nathaniel Sprague is living in Connecticut, whose birth information is a good match. No wife is listed.
Prior to the marriage in 1866, everything is speculative and uncertain. There is a Nathaniel Sprage who married Nashua, NH, 1839 to Mary A Taylor. This Nathaniel is living in Gloucester, MA, in 1860, but the age listed is only a marginal match (but matching that in 1870 which is known to be him). In 1865 the wife Mary is listed as Widowed with children and no husband in Gloucester. If her husband was this Nathaniel, who married a year later, then they divorced. But more evidence is needed to make such a conclusion.