The 1880 United States census showed Ernest Jacobi (age 8, born in Canada) living with Gustave (age 13, born in Canada), Lillie (age 9, born in Canada), and Isabella R. (age 6, born in Canada) in Turtle River, Grand Forks County, Dakota Territory.

The 1885 Dakota Territory census showed Ernest Jacobi (age 12, born in Canada) living in Grand Forks County, Dakota Territory, with his parents Ernst (age 46, born in Germany) and Ellen (age 38, born in Ireland). His other siblings were Lilian (age 14, born in Canada) and Isabella (age 10, born in Canada).

The 1889-92 Grand Forks City Directory showed Ernest R. Jacobi living at 522 South Fourth.

Ernest R. Jacobi. President of Jacobi Elevator Company, Vice-President of the First National Bank, Residence in Grand Forks, North Dakota. (1893 East Grand Forks City Directory, William L. Dudley, Chester Fritz Library/University of North Dakota)

The 1895 Minnesota census showed Ernest Jacobi (age 27, born in Canada) living in Duluth, Minnesota.

The 1900 United States census showed Ernest Jacobi (age 27, born in December 1872 in Canada, merchant) married to Adelaide B. (age 20, born in December 1879 in Michigan) and living in Duluth, Minnesota. A daughter, Isabelle (age 2 months, born in April 1900 in Minnesota), also lived with the couple.

The 1910 United States census showed Earnest Jacobi (age 37, born in Canada, grain merchant) married to Adelaide (age 30, born in Michigan) and living in Duluth, Minnesota. A daughter, Isabel (age 10, born in Minnesota), also lived with the couple.

The 1920 United States census showed Earnest Jacobi (age 46, born in Canada, grain merchant) married to Adelaide (age 38, born in Michigan) and living in Duluth, Minnesota. A daughter, Isabel (age 19, born in Minnesota), also lived with the couple.

The 1930 United States census showed Ernest Jacobi (age 56, born in Canada, grain merchant) married to Adelaide (age 48, born in Michigan) and living in Duluth, Minnesota.

Ernest Jacobi died April 6, 1953, in St. Louis County, Minnesota.