Mary Fields was born enslaved in Tennessee in 1832. Post-emancipation, she worked at a convent. She later followed one of the nuns, Mother Amadeus, to Montana where she had set up a school for Indigenous girls in Montana yet had fallen gravely ill. Fields saved the freezing, starving students by hunting, farming, and hauling supplies and dry goods. In 1895, Fields received a contract to drive horse and wagon for the Star Route, a service started by the U.S. Postal Service using contracted workers to protect and deliver mail to sparsely populated places. The first known African American woman Star Route mail carrier in the United States, she worked the dangerous 34-mile route for two four-year contracts: 1895–1898 and 1899–1903.