Mary “Polly” Heavner was born 12 March 1802 in Pendleton County, Virginia to Nicholas Heavner and Maria Sophia Propst.
On 23 December 1819, in Lewis County, Virginia, she married Daniel Post. They had thirteen children in the order of birth: Abraham Jefferson, Jemima, Jacob, Isaac, Anna, Stephen, Mary Jane, Sena, Nicholas, George Washington, Christena, Ellen Elizabeth, and Sarah.
Mary Heavner Post died on 20 July 1881 at Rooting Creek, Uphur County, West Virginia. She is buried in Johnstown Cemetery in Harrison County, West Virginia.