The McMahon family is first found in the 1900 Federal Census in Brisbin Borough, Clearfield County, Pennsylvania. Names and dates of birth conflict with other records, but this is the correct family: James, a coal miner b Mar 1861 in England; Catherine, b Aug 1863 in Pa., 7 children/7 living; Sarah, b Sept 1883; "Ellen," b Oct 1886; Catherine, b Apr 1889; Anne, b Dec 1891; Maria, b Mar 1891; James, July 1896; Leonard, b Jan 1889. Also in the home was Catherine's father, Patrick "O'Donald."

Sarah's sister, Helen McMahon graduated in the St. Francis School of Nursing Class of 1909.

At the time of the 1920 census, Sarah B. McMahon was living on Broad Street, Pittsburgh, and was employed as a nurse for a private family. Her two roommates were nurses, Rose McMahon and Anna C. King. - Rose McMahon graduated in the St. Francis Class of 1909 with Sarah's sister, Helen. Anna King graduated in the Class of 1912, with Sarah.

Sarah and her parents were residents of Penn Avenue, Pittsburgh in the 1930 census. She is listed as a "Trained Nurse, Hospital," age 46. Her father was 73 and he died after this census.

In 1940, Sarah and her mother were living on Main Street, Pittsburgh, with Sarah's sister, Catherine, wife of Bernard McCann. Sarah was a Private Duty Nurse. Her mother died in 1949.

At St. Francis Hospital, on February 14, 1950, Sarah B. McMahon, born Sept 2, 1885, died of Meningitis. Her death record confirms her parents as James McMahon and Katherine/Catherine O'Donnell. Her sister, Helen (McMahon) Hillman, 120 Mathilda St., Pittsburgh, was the informant.

Sarah is buried at Calvary Cemetery, Pittsbugh. The gravestone is for both mother, Catherine, 1866-1949, and "Sara B.," 1885-1950.