When Mary A. Stearns was born in December 1870, in Clay, Onondaga, New York, United States, her father, Charles Lucius Stearns, was 39 and her mother, Sarah J Newport, was 30. She married John Sleeth on 16 October 1889, in West Virginia, United States. They were the parents of at least 1 son. She lived in Cicero, Onondaga, New York, United States in 1900. She died on 7 June 1949, in Syracuse, Onondaga, New York, United States, at the age of 78.