In the 1880 US Census for District 116, Newtown, Fairfield County, Connecticut the family of Eli C. Barnum was enumerated as follows:
Dwelling #271; Family #281
Barnum, Eli C.; W; M; 34; Married; Farmer; b. Connecticut; Both parents b. Connecticut
Barnum, Charlotte F.; W; F; 34; Wife; Married; Keeping house; b. Connecticut; Both parents b. Connecticut
Barnum, Edith C.; W; F; 8; Daughter; Single; At school; Attended school within the census year; b. Connecticut; Both parents b. Connecticut
Barnum, Robert G.; W; M; 5; Son; Single; At school; Attended school within the census year; Cannot write; b. Connecticut; Both parents b. Connecticut
He is buried in the Village and Town Plot Cemetery. His gravestone reads: Barnum, Eli Cornwall, born Dec. 25, 1845, died Oct. 17, 1933.