Rose McMahon, born April 14, 1882, was the daughter of John W. McMahon, born in Ireland, and Jane Fitzsimmons, born in Blair County, Pennsylvania. The father died in the late 1880s and the mother married Patrick Mulhern.

At the time of the 1920 Federal Census, Rose McMahon, 34, born in Pennsylvania, was living with two other nurses, Anna C. King and Sarah B. McMahon, on Broad Street, Pittsburgh. Anna C. King and Sarah B. McMahon graduated in the St. Francis Class of 1912. Rose graduated in 1909 with Sarah's sister, Helen McMahon.

"Rose McMahon" is named in a 1922 history of the Pittsburgh Red Cross as a St. Francis graduate enrolled at the Pittsburgh Chapter and a nurse at the University of Pittsburgh Base Hospital No. 27 during World War I. She served with the American Expeditionary Forces during World War I, and is named in this article: Nurses Given Great Ovation By Pittsburgh.

Rose McMahon married Dr. Thomas McSwiney Barrett, a neuro-psychiatrist, in 1926. Dr. Barrett died March 27, 1948 and is buried at St. Mary's Cemetery, Pittburgh.

Rose died in Pittsburgh, Allegheny County, on November 28, 1976. She, too, is buried at St. Mary's Cemetery.