).O'Mahoney was prominent in the women's branch of the Irish Land League; founder and president of the Aventine Literary Club, and of the Orphans' Friends' Society, of Lawrence County; organizer of a division of the Ladies' Auxiliary, Ancient Order of Hibernians, its president for five years, and Essex County president for two years.She was secretary of the Essex branch, Boston Archdiocesan Union of the American Federation of Catholic Societies; organizer and first president of St. Mary's Alumni Association; and vice-president of Lawrence Anti-Tuberculosis League.