In the U.S. Census of 1900 for District 0182, Salem East Ward, Salem County, New Jersey, the family of William Barnum was enumerated as follows:
Dwelling 24; Family 24 (Pledger Street)
Barnum, William; Head; White; Male; b. Dec 1832; 67; Married 30 years; b. Connecticut; Both parents b. Connecticut; Stone mason; Unemployed 4 months during the census year; Can read,write and speak English; Rents non-farm home
Barnum, Phineas T.; Son; White; Male; b. July 1877; 23; Married 2 years; b. New York; Father b. Connecticut; Mother b. New York
William's wife, Margaret, was enumerated with the family of Ernest Wiser in the house next door, as follows:
Dwelling 23; Family 23 (Pledger Street)
Wiser, Ernest; Head; White; Male; b. May 1864; 36; Married 10 years; b. Pennsylvania; Both parents b. Pennsylvania; Plasterer; Out of work 5 weeks during the census year; Can read, write and speak English; Rents non-farm home
Wiser, Crissy E.; Wife; White; Female; b. May 1864; 36; Married 10 years; Mother of 4 children; b. New Jersey; Both parents b. New Jersey; Can read, write and speak English
Barnum, Margaret; White; Female; b. Aug 1837; 66 [sic, s/b 63]; Divorced; b. New York; Father b. France; Mother b. New York; Can read, write and speak English
Note: As may be seen above, Margaret was shown as divorced and William as married 30 years. However, Margaret had been shown originally as married 30 years and that notation was later erased and "D" for divorced added in the column for number of children. That same "D" notation was also placed in the column for number of children in William's enumeration. Margaret also appears as a member of the family of her son, P.T. Barnum, in the US Census of 1910 where she is enumerated as divorced. It may be safely assumed, therefore, that the couple had divorced prior to 1 Jun 1900, the date of the 1900 Census enumeration.
In this census enumeration, when we may assume that the informant was William himself, he gave his birthplace as Connecticut. In later census enumerations, when he was probably no longer living, his birthplace was given by others as "at sea".