Mary Arthur McElroy

Mary Arthur McElroy ( born July 5, 1841 in Greenwich, New York, † January 8, 1917 in Albany, New York) was the sister of U.S. President Chester A. Arthur, and was First Lady from 1881 to 1885. The wife of the president, Ellen Arthur, had died before the start of the Presidency, so Mary had taken office.

Her parents were William and Malvina S. Arthur. She was the youngest of nine children. With her husband John McElroy they had four children.

After the end of the presidency of her brother Mary moved to Albany, where he died at the age of 75 years. She is buried in the Albany Rural Cemetery.