The 1870 United States census showed Oscar Bierbauer (age 15, born in Pennsylvania) living with his parents Jacob (age 51, born in Bavaria, woolen manufacturer) and Bertha (age 37, born in Saxony) in Mankato, Minnesota. His siblings were Ida (age 12, born in Minnesota), Emma (age 10, born in Minnesota), Elmore (age 8, born in Minnesota), and Eugene (age 3, born in Minnesota).
The 1895 Minnesota census showed Oscar Bierbauer (age 39, born in Pennsylvania, register of deeds) married to Emily (age 39, born in Wisconsin) and living in Mankato, Minnesota. Children Elvira (age 3, born in Minnesota) and Erna (age 3, born in Minnesota) also lived with the couple.
The 1900 United States census showed Oscar J. Bierbauer (age 44, born in September 1855 in Pennsylvania, malt and grain dealer) married to Emily (age 42, born in November 1857 in Wisconsin) and living in Mankato, Minnesota. Children Elvira Q. (age 8, born in January 1892 in Minnesota), Erna C. (age 6, born in May 1894 in Minnesota), and Norma L. (age 1, born in August 1898 in Minnesota) also lived with the couple.
The 1905 Minnesota census showed Oscar Bierbauer (age 49, born in Pennsylvania, brewer) married to Emma (age 47, born in Wisconsin) and living in Mankato, Minnesota. Children Elvira Olga (age 13, born in Minnesota) and Norma Lilian (age 6, born in Minnesota) also lived with the couple.
Page 44. Bierbauer, Oscar, maltster; born in Erie, Pa., Sept. 22, 1855; son of Jacob and Bertha (Dornberg) Bierbauer; educated in Mankato public schools; widower. Came to Minnesota with parents, Oct., 1856; engaged in re-distilling and rectifying liquors, in Milwaukee, Wis., for 10 years; returned to Mankato, 1881, and was in Old Pioneer Mills, for 5 years; register of deeds Blue Earth Co., 1887-97; has been president and treasurer of the Mankato Malting Co., since its establishment, 1902.
Page 45. Also president Mankato Brick Co. President Board of Education 6 years; member Library Board. Republican. Member Masonic order, Knight Templar, I. O. O. F., A. O. U. W., B. P. O. E. Club: Commercial. Address: Mankato, Minn. (The Book of Minnesotans, A Biographical Dictionary of Leading Living Men of the State of Minnesota, Albert Nelson Marquis, A. N. Marquis & Company, Chicago, 1907)
The 1910 United States census showed Oscar Bierbauer (age 55, born in Pennsylvania, real estate agent) living with his mother Martha (age 78, born in Germany) and sister Alma (age 47, born in Minnesota) in Mankato, Minnesota. Children Alveria (age 18, born in Minnesota) and Norma (age 12, born in Minnesota) also lived with the family.
The 1920 United States census showed Osker Bierbaur (age 65, born in Pennsylvania, cement worker) living in Mankato, Minnesota. A daughter, Norma (age 21, born in Minnesota), also lived Oscar.
The 1930 United States census showed Oscar Bierbauer (age 74, born in Pennsylvania) living in Minneapolis, Minnesota. Daughters, Elvira (age 38, born in Minnesota, teacher) and Norma (age 31, born in Minnesota, secretary), also lived Oscar.
Oscar Bierbauer died February 15, 1936, in Hennepin County, Minnesota.