There is no proof that the Robert Langworthy who married Mary Green was the son of Sanford, but:

* We know from the testimony of a relative that Sanford had a son named Robert.

* We know that Robert was alive in 1846 because a letter written then (see WFL, p.205) says that “Robert had worked for writers considerable of the time.”

* There’s no other known candidate - all of the other Robert Langworthys of about the right age appear elsewhere.

Robert’s birth date comes from the Greenwich, NY vital records for 1848:
“Robert Langworthy, 28 yrs, of Greenwich married Mary Green, 30 yrs, of Easton at Galesville (Middle Falls) 7 May 1848.”

I have not found any later records of Robert in Washington Co.

However a Robert Langworthy of the right age appears in the 1850 Census of Oswego Co. NY. The only other Langworthys in Oswego Co. were descendants of Sanford (1776). Because - once again - there are no other known candidates, it seems reasonable to assume this is the same Robert. He actually appears twice - once in West Monroe where he was a farmer, and again in Constantia where he was a sawyer, probably a cash-producing job.

In West Monroe he married Waity Herrington and soon thereafter moved to Wisconsin, where the adjacent family was headed by John Herrington, perhaps a relative of Waity.

Census Tracking:
* 1850 - Constantia, Oswego Co., New York
and West Monroe, Oswego Co., New York (double count)
* 1855 State Census of Sacramento, Waushara Co., Wisconsin (R. Longworth)
* 1860 - Aurora, Waushara Co., Wisconsin