She received widow's pension, certificate no. 61579, for the Civil War service of her husband.
The 1920 US Census for Benton County, Minnesota shows the birthplace of Ida A. (Holmes) Barnum as New York. However, her death certificate and earlier census data give her birth state as Illinois.
In the 1927 City Directory for Saint Cloud, Minnesota, is found the following listing: Barnum, Ida (wid Ira A) h300 Broadway av N
In the 1930 US Census for Minneapolis, Hennepin Minnesota she was widowed and was enumerated living with her daughter and son-in-law, Rose M. and Isaac Newton Smith.
Ida A. (Holmes) Barnum died at the age of 83 years, 1 day, of coronary sclerosis, at the home of her daughter Rose Barnum (Mrs. I. N. Smith) at 601 Forest Avenue, Minneapolis, Minnesota. At the time of her death, she had been living in Minneapolis for about 11 years. She apparently moved there shortly after the death of her husband, Ira Barnum, which occurred in 1921.