Mary Josephine Duff was born in Rantem, Newfoundland on May 9, 1888. Her parents were Edward J. Duff and Mary Daley. (Baptism record gives birth year as 1889.)

In 1920, Mary J. Duff, 30, and Madeline Duff, 27, both aliens, both born in Newfoundland, were living on Kincaid Street, Pittsburgh. Mary J. was employed as a nurse for a private family, and Madeline was a telephone operator.

Mary had served as a nurse in the US Army Reserves during World War I. She was a resident of New York at the time she filed her application for compensation in 1934.

Nothing more is known about Mary Josephine Duff.

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