"Ohio, County Marriages, 1789-2013," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XD76-PMT : 26 August 2019), John M. Smith and Mary O'Neal, 24 Apr 1845; citing Marriage, Allen, Ohio, United States, p 75, Franklin County Genealogical & Historical Society, Columbus; FHL microfilm.
"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MZ17-X64 : 11 September 2017), John Smith, 1880; citing enumeration district ED 224, sheet 507A, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d), roll 0990; FHL microfilm 1,254,990.
It may be possible to confirm family relationships with John by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with John: