In the 1870 US Census for Menomonie, Dunn, Wisconsin, the family of Thomas BARNUM was enumerated as follows:
Household #170; Family #182
Barnum, Thomas; 30; M; W; Works in M.; real property $500; b. New Y'k
Barnum, Angeline; 24; F; W; Keeps House; b. Ill.
Barnum, Wm.; 7; M; W; b. Wis.; Attended school during previous year
'The Barnum Family, 1350-1907' [Source] seems to indicate that he was
born
in Seattle, Territory of Washington. However, it seems that his
family
did not arrive in that area until about 1848, and the city itself was
not
laid out until 1853.