There are several John W Bakers from this area in VA on familysearch.org. You might want to look at the various data and see who matches.
https://familysearch.org/search/records/index#count=20&query=%2Bgivenname%3A%22john%20w%22~%20%2Bsurname%3Abaker~%20%2Bbirth_place%3AVA~%20%2Bbirth_year%3A1850-1852~
examples below:
Jno W Baker
U S Census 1860 Loudoun, Virginia
birth: 1852 Loudoun
Jno. W. Baker
Virginia, Marriages,
birth: 1852 Loudoun Co., Va.
marriage: 30 Nov 1875 Loudoun, Virginia
parents: Jos. C., Mary J.
spouse: Sarah A. Fry