Mary McElroy was an American woman known as being the sister of the 21st president of the United States, Chester A. Arthur, for whom she served as a hostess for his administration (1881–1885). She assumed the role because Arthur's wife, Ellen, had died nearly two years earlier.
- Occupation
- politician
- Position held
- First Lady of the United States
- Citizenship
- United States
- Born
- July 5, 1841
- Died
- January 8, 1917, 1916
