Born in Scrubgrass Township of Venango County, Pennsylvania, Mary was the daughter of Dr. John and his second wife, Elizabeth (Baird) Coulter Jr. On June 5, 1866, she married Thomas Jefferson Eakin Sr. (1840-1894), son of David and Rebecca Stalker Eakin of Scrubgrass Township in Venango County, Pennsylvania. Before their marriage, Thomas had served with the PA Volunteers in Company E of the 16th Cavalry Regiment during the Civil War. After his discharge in 1865 near Lynchburg, Virginia, he returned home and he and Elizabeth were married the following year.
Thomas was a farmer and served as County Commissioner in 1881 and was reelected in 1884. He was aslo twice elected as Justice of the Peace in Clinton township along with being the postmaster in the town of Emlenton. Thomas died at home after after suffering from bowel disease. After Thomas's death, Mary applied for Thomas' Civil War pension in 1895.
About 1896, she sold the farm, moved with nine of her twelve children to Colorado and bought a house in Florence, Fremont, Colorado. Her oldest son, Charles was employed in the oil industry there. By 1910, most of the children had struck out on their own (two of the boys died shortly after moving to Colorado). Her daughter, Sarah was teaching school and her son, Louis Donald was working as a clerk in a real estate office.
Mary and Thomas Eakin Sr. were the parents of twelve children: Mary Alice, Charles Preston, Mary Elizabeth (Porter), Sarah Rebecca, John Howard, David Bertrand, Thomas Jefferson Jr., Martha Amelia (Bell), Samuel Marshall, Ada Caroline, James Harold and Louis Donald Eakin.

From "Scrips and Scraps," abstracts from six old scrapbooks courtesy of nbr:

Mrs. Martha Coulter has been advised of the death of her sister, Mrs. Mary Adaline Eakin, which occurred at the home of her daughter and husband, Dr. and Mrs. Bell, of 1640 Logan street, Denver, Col., on March 12 following illness of pneumonia. On March 26 she would have been 86. Wife of late T. J. Eakin, former county commissioner and postmaster of Emlenton, passing away while he was
in that service. Survived by two daughters, Mrs. James B. Porter of Tulsa and Mrs. Bell, with whom she lived for several years, and four sons, Marshall of Tulsa; Harold of New York city; Howard of western oil fields and Donald of Idaho.
Funeral at Presbyterian church at Florence, Col, where she lived for several years after leaving Emlenton. Dr. Birchfield, present pastor, officiated. Hymns sung, many floral offerings.... (March 15, 1931)