In September 1920, Mary Margaret Timmons, born in Ireland, a Registered Nurse, became a Naturalized Citizen. According to her application, she was born on June 9, 1882 at Casteldermot, (in County Kildare), Ireland. She left Dublin, Ireland on the vessel Baltic, on October 15, 1910, and arrived in New York on October 22, 1910.

Mary M. Timmins is named in a 1922 history of the Pittsburgh Red Cross as a St. Francis nurse graduate who was "in active service with the American Expeditionary Forces and in the United States."

U. S. Veterans' Gravesites: Mary Margaret Timmins - Service Info.: RES NURSE ARMY NURSE CORPS USA - Birth Date: 8 Jun 1882 - Death Date: 16 Apr 1966 - Interment Date: 20 Apr 1966 - Cemetery: Arlington National Cemetery Cemetery, Arlington, VA 22211 - Buried At: Section 21 Site 578.

Mary M. Timmins was a member of Post 509, Kathryn Mae Joyce Post, Nurses of the American Legion, in Pittsburgh.

In 1930, Mary Timmins, born in Ireland , a trained hospital nurse, born about 1883, lived at and worked as a nurse at the Veterans Hospital in Aspinwall, Allegheny County.

According to the Social Security Death Index, Mary M. Timmons' last residence was Perry Point, Cecil County, Maryland.