When Mary Gwaltney was born on 17 June 1821, in Posey, Indiana, United States, her father, Thomas Gwaltney, was 24 and her mother, Nancy Patsy Reeder, was 18. She married Joshua Reeder on 18 March 1841, in Posey, Indiana, United States. They were the parents of at least 4 sons and 7 daughters. She lived in Illinois, United States in 1870 and Little Caney Township, Chautauqua, Kansas, United States in 1880. She died on 25 December 1885, in Chautauqua, Kansas, United States, at the age of 64, and was buried in Chautauqua, Chautauqua, Kansas, United States.
Anglicized form of the Welsh surname Gwalchmai, which is from the Welsh personal name Gwalchmai ‘hawk of the plain’.