In the 1850 US Census for Burns, Shiawassee County, Michigan the family of John B. Barnum was emumerated as follows:
Dwelling #69; Family #69
John Barnum, 54, M, Farmer, Real property $1,500, b. New York
Martha Barnum, 50, F, b. New Jersey [second wife]
Isaac Barnum, 23, M, Farmer, Real property $100, b. New York
Jane Barnum, 25, F, b. New York
Amos S. Barnum, 50, M, Farmer, b. New York [Amos has not been identified, although he was probably a brother or cousin of John]
The family of John's son Abijah was living next door.
From Pages 198/199 History of Shiawassee and Clinton Counties, MI, 1880, pp 198/199: John B. Barnum, who, on June 22, 1836, settled on the northwest quarter of section 28, was probably the next settler in Burns. He built a log house on this farm, and after the expiration of a year and a half he traded it to William Baulch for part of the southeast quarter of section 26. The farm first entered by Mr. Barnum is now owned by S. S. Wiltsie, who purchased it in 1843. Mr. Barnum built on his new farm a house and barn, which are still standing. His family at the time of settlement consisted of a wife and four children, and a half-brother, familiarly known in the early days as Uncle Tommy. John B. Barnum died Feb. 5, 1865. His first wife, Urena, had died May 24, 1848 and his second wife died in February 1880. His son, Isaac S. Barnum, married Amelia, the daughter of Robert Crawford. They live on section 26, near the site of the old homestead.
The Genealogical Record of the Barnum Family states that he was born in Lockport, New York.