Mary was born in Catlettsburg, Carter County (now Elliotts County), Kentucky on 27th April 1867; the daughter of Benjamin and Nancy (née Kegley) Elliott. She married William Harvey Flanery of Sandy Hook, Carter County, on 28th June 1893, and had five children, Sue, Merle, Dawn, Dew and John Elliott.
Mary graduated from Barboursville College (now University of Charleston in West Virginia) and the Agricultural and Mechanical State College (now University of Kentucky), and initially worked as a teacher. She then worked as a journalist for the Ashland Daily Independent newspaper from 1904 to 1926.
In 1921, she was the first woman elected to the Kentucky General Assembly and served as a state representative from Boyd County. She was also the first woman south of the Mason-Dixon Line to be elected to a state legislature.
She worked for woman suffrage and educational reform, and was concerned with Kentucky marriage and divorce laws. She sponsored the Shepard-Towner Maternity Act and also sponsored the bill establishing Morehead State Teachers College. In 1924, she was chosen as a delegate to the Democratic National Convention in New York City.
Mary died on 19th July 1933, and is buried in Ashland Cemetery. After her death, a bronze plaque was placed at her seat (#40) in the house chambers to commemorate her service to the Commonwealth of Kentucky.
[her portrait is illustrated above; courtesy of the University of Kentucky]