Old Elizabeth (1766-1866)
Memoir of Old Elizabeth, a Coloured Woman
She was an emancipated slave (freed by her fourth owner), born in Maryland. She began preaching at the age of 42, evangelizing from Virginia as far North as Canada. She founded an orphanage for black children in Michigan, which was staffed by white teachers to lessen opposition. Her final days were spent in Philadelphia, where her memoir was published.
http://www.learnnc.org/lp/editions/nchist-newnation/5203 (exercpt from the memoir)