When Mary Estelle Mix was born in September 1874, in Pennsylvania, United States, her father, Charles Frederick Mix, was 19 and her mother, Cora Sardinia Witter, was 16. She had at least 4 sons and 5 daughters with Delos Leland Marsh. She lived in Andover, Allegany, New York, United States in 1915 and Andover, Andover, Allegany, New York, United States for about 10 years. She died on 4 June 1952, in Wellsville, Wellsville, Allegany, New York, United States, at the age of 77, and was buried in Wellsville, Wellsville, Allegany, New York, United States.