Mary (who was sometimes called Maria) was born in 1778 at Monticello. Her parents were Martha and Thomas Jefferson. When her mother died, Mary was only four years old.

Jefferson sent Mary and her younger sister Lucy to live with their aunt. Soon little Lucy died. Jefferson often wrote Mary. He asked about her schooling, "How goes the Spanish?" He asked about her life, "How many chickens have you raised this summer?"

Mary liked her new family. When she was eight years old, Jefferson wanted her to join him in France. Her older sister Martha was in France, too. Mary wrote her father "I don’t want to go to France, I had rather stay with Aunt Eppes."

Mary was nine when she traveled to France. Jefferson asked Martha to help raise Mary. He wrote, "Teach her above all things to be good. Teach her to be true." In Paris, the two girls went to school. Mary studied literature, drawing and music.

In 1797, Mary married John Wayles Eppes, her cousin. She gave birth to three children. Her son Francis lived to be an adult. Mary was only twenty-six when she died.