Mary was the daughter of unknown parents. The date and place of her birth have not been found.
Her husband was Alexander Campbell McCreath, who she married on 12 JAN 1934 in Gorbals. Their seven known children were Mar (1934-?), Alice Pritchard (1935-?), Robert Pritchar (1936-1996), Alexande (1940-1991), Isabella Campbell (1943-?), Margaret Pritchar (1944-?) and George Bel (1948-?).