In the 1850 US Census for Troy, Richland County, Ohio the family of Levi Barnum was enumerated as follows:
Dwelling #54; Family #54
Levi Barnum, 64, M, Farmer, Real property $2,500, b. Vermont
Merciee [sic] Barnum, 64, F, b. Vermont
Sarry Ann [sic], F, 18, b. Vermont
[Note: Mercy Barnum would have been 55 years old at the time of this census].
The Independent State of Vermont was constituted on 2 June 1777, and joined the Union as the 14th state on 4 March 1791.
'The Barnum Family, 1517-1904' gives him a death year of 1851.