Elmer was the son of Nels and Jane Mellum, who came to Ypsilanti in 1904, buying farmland two miles east of Ypsilanti. Anna was the daughter of Carl and Lena Janz.
Elmer and Anna were married on June 15, 1939 in Montpelier, and moved to the Mellum family farm east of Ypsilanti. Elmer had been born on this farm, and he lived there all of his life, which ended on January 8, 1978.
Elmer Mellum served on the Ypsilanti Township Board for twenty-six years, as well as on the A.S.C. Committee, and on the board of the Ypsilanti Lutheran Church. He coached the Ypsilanti baseball team.
Before her marriage, Anna attended Valley City State Teachers College, and had taught schools in Corwin and Sharlow townships. She also taught Sunday School, and was the Sunday School superintendent at the Ypsilanti Lutheran Church for many years.
They had two children: Kay and Elton.