Ralph Plumb (29 March 1816-8 April 1903) was a member of the US House of Representatives (R-IL 8) from 4 March 1885 to 3 March 1889, succeeding William Cullen and preceding Charles A. Hill. Born in Busti, New York, he moved to Ohio and practiced law in Oberlin before serving in the Union Army during the American Civil War. He relocated to Streator, Illinois in 1866 and served as mayor from 1882 to 1885 and in Congress from 1885 to 1889, and he engaged in banking until his death in 1903.