Thomas died on 6 July 1926 in Alexander in the Banks district of Upshur County, West Virginia.His death certificate lists his last name as Johnson, but the informant for the death certificate (who unfortunately did not know his grandparents names) was Will Johnson.This Thomas Johnson farmer and a widower when he died.His birth date is listed as 24 July 1844 in WVa (which would have been Virginia in 1844).The death certificate image is here: http://www.wvculture.org/vrr/va_view.aspx?Id=1893091&Type=Deathhttp://www.wvculture.org/vrr/va_view.aspx?Id=1893091&Type=Death
At the time of the 1910 census Thomas F. Johnston is living in Banks, Upshur, West Virginia, in the following household: Household Gender Age HeadThomas F JohnstonM 65y SpouseElla M JohnstonF 66y ChildWilliam T JohnstonM 33y ChildSarah E JohnstonF 23y (I believe this is a daughter-in-law) Grandson Asa M JohnstonM 4y Grandson Oliver I JohnstonM 3y Granddaughter May A JohnstonF y 10m The census record is here: https://familysearch.org/pal:/MM9.1.1/MPNS-L8X
For the 1900 census, Thomas and Ella were Johnsons again, in the Banks district of Upshur County.The household consisted of: Thomas F. Johnson born July 1844 in Virginia (parents born in Virginia) Ella M. Johnson born April 1842 in Ohio (both parents born in New York) William T. Johnson born March 1877 West Virginia Sarah May Johnson born October 1878 West Virginia Lattie M. Johnson born January 1882 Ohio The census image is here: https://familysearch.org/pal:/MM9.3.1/TH-266-11871-70997-65?cc=1325221
For the 1880 census the family was in Moorefield, Harrison, Ohio and the household consisted of: HeadThomas F. JohnsonM 36 SpouseEllen N. JohnsonF 27 ChildCharles D. JohnsonM 5 ChildWilliam JohnsonM 4 ChildSarah M. JohnsonF 1 Census record is here: https://familysearch.org/pal:/MM9.1.1/M897-HJF
The family appears to have been Johnsons more often than Johnstons, but so much of what showed up in the censuses or vital records depended on the ear of the listener who recorded it.