Smith Ely, Jr. (April 17, 1825 - July 1, 1911) was a Mayor of New York City and Representative from New York.

Born in Hanover, Morris County, N.J., 1825, he completed preparatory studies and was graduated from the New York University Law School, New York City, in 1846. He was admitted to the bar the same year, but never practiced his profession; and engaged in mercantile pursuits in New York City.

He was active in various public offices:

• served as school commissioner 1856-1860;
• served in the State senate in 1858 and 1859;
• county supervisor in 1860-1870;
• commissioner of public instruction in 1867;
• elected as a Democrat to the Forty-second Congress (March 4, 1871-March 3, 1873); was not a candidate for renomination in 1872;
• elected to the Forty-fourth Congress and served from March 4, 1875, to December 11, 1876, when he resigned; chairman, Committee on Expenditures in the Department of the Treasury (Forty-fourth Congress);
• mayor of New York City in 1877 and 1878;

In 1895, he was appointed commissioner of parks and served until 1897, when he retired from public life; died in Livingston, Essex County, N.J., 1911; interment in a private cemetery on his farm at Livingston.