The McMahon family is first found in the 1900 Federal Census in Brisbin Borough, Clearfield County, Pennsylvania. There are conflicts with other records, but this is the 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."

"Helen 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.

New York, New York City Marriage Records, 1829-1940----Helen McMahon, 34 [age understated], the daughter of James McMahon and Kathryne O'Donnell, born in Huntsdale [sic - Houtzdale], Pennsylvania, married Ernest Hillmann, 37, in Manhattan, New York, on May 27, 1927. He was born in Sheboygan, Wisconsin, and his parents were John and Hilda (Pufevgel).

In 1934, based on her service as a Reserve Nurse during WWI, Helen applied for Veteran's Compensation, at which time she was a resident of a Veterans' Facility in Hines, Illinois. For reasons unknown, Warren (Pa.) National Bank was Helen's Guardian. The application indicates that her husband was Ernest Hillman, but his address was unknown. The pension application names her parents as Katherine O'Donnell, Pittsburgh, and James McMahon, deceased. It says she was born in Houtzdale, (Clearfield County), Pennsylvania on October 7, 1885.

On April 11, 1949, a notice was published in the Warren Times Mirror: Notice is hereby given that the First and Final Account of Warren National bank, Guardian of Helen McMahon Hillman, will be presented to the Court of Common Pleas for confirmation on May 1, 1949, at ten o'clock a.m....

At St. Francis Hospital, on February 14, 1950, Sarah B. McMahon, born Sept 2, 1885, died of Meningitis. She was Helen's sister, another daughter of James and Katherine. Helen Hillman, 120 Mathilda St., Pittsburgh, was the informant. Sarah, a trained nurse, graduated in the St. Francis Class of 1912. She is buried at Calvary Cemetery, Pittsbugh. The gravestone is for both mother, "Catherine," who died in 1949, and Sara B. (1885-1950).

Helen is listed in the Pittsburgh City Directory, 1952, still living on Mathilda Street.

Her date of death is not known. There is a WWI nurse, Helen M. Hillman, buried at Long Island National Cemetery, Farmingdale, NY: DATE OF BIRTH: 10/30/1889 - DATE OF DEATH: 12/26/1974. Inconclusive.