1880 census shows Ann to be a widow, living at 182 S Main St in Waterbury, CT
It also shows 3 sons - James B, 25, Machinist, John E, 23, Saloon Keeper, and Arthur M, 21, At Home.
Interesting, too that I find James B listed separately in the 1880 census, and I'll attach that listing. Find also that Arthur M was born 6/4/1860 in CT and died 8/27/1883. If you're interested, I'll try to find more info for you.
Mary L (lilychap@cox.net)
https://familysearch.org/pal:/MM9.1.1/MFCP-28W
Name: James B. Agnew
Residence: Waterbury, New Haven, Connecticut
Birthdate: 1854
Birthplace: Connecticut, United States
Relationship to Head: Self
Spouse's Name: Catharine Agnew
Spouse's Birthplace: Massachusetts, United States
Father's Name:
Father's Birthplace: Connecticut, United States
Mother's Name:
Mother's Birthplace: Ireland
Race or Color (Expanded): White
Ethnicity (Standardized): American
Gender: Male
Martial Status: Married
Age (Expanded): 26 years
Occupation: Machinist
NARA Film Number: T9-0103
Page: 133
Page Character: A
Entry Number: 4547
Film number: 1254103
Collection: United States Census, 1880