In the 1850 US Census for New Haven, New Haven County, Connecticut the family of Alonzo Barnum was enumerated as follows:
Dwelling #2047; Family #2976
Alonzo Barnum, 29, M, Carpenter, Real property $500, b. Connecticut
Flora Barnum, 24, F. b. Connecticut
Caroline Plumb, 21, F, b. Connecticut
A record exists for an Alonzo P. Barnum of Fitchburg, Massachusetts who enlisted in the Army as a Private on 23 August 1862, at the age of 43 years.
Source Information: 1880 Census Place Danbury, Fairfield, Connecticut, Family History Library Film 1254094, NA Film Number T9-0094, Page Number 117B, Alonzo BARNUM Household, Male, Other Information: Birth Year <1821>, Birthplace CT, Age 59, Occupation Carpenter, Marital Status M , Race W , Head of Household Alonzo BARNUM, Relation Self, Father's Birthplace CT, Mother's Birthplace CT.
Although he was married, Alonzo Barnum died without issue.