Mary Easton was born on January 24, 1800 to Mr. and Mrs. Rufus Easton in Rome, New York. In 1804, Rufus Easton moved the family to St. Louis to pursue his new appointment as the first Post Master of St. Louis in the newly acquired Louisiana Territory.
Mary completed her education at Mrs. Tivis Boarding School for Young Ladies in Shelbyville, Kentucky. Upon finishing her education she was well versed in Latin and French. At age 15, she married George Sibley the factor at Fort Osage. In 1816, the couple, along with Mary’s Sister, moved to Fort Osage.
In 1826, the Sibley’s moved to St. Charles, Missouri. It was here that Mary Sibley’s high sense of humanity led to her greatest contribution, the founding of Lindenwood College. Until her death in 1878, she took an active role in community affairs and women’s rights. Mary Sibley’s death occurred in Lindenwood where she is buried beside her husband, George Sibley.