1900 United States presidential election in Illinois

The 1900 United States presidential election in Illinois took place on November 6, 1900. All contemporary 45 states were part of the 1900 United States presidential election. State voters chose 24 electors to the Electoral College, which selected the president and vice president.

Illinois was won by the Republican nominees, incumbent President William McKinley of Ohio and his running mate Theodore Roosevelt of New York. They defeated the Democratic nominees, former U.S. Representative and 1896 Democratic presidential nominee William Jennings Bryan and his running mate, former Vice President Adlai Stevenson I. McKinley won the state by a margin of 8.39% in this rematch of the 1896 presidential election. The return of economic prosperity and recent victory in the Spanish–American War helped McKinley to score a decisive victory.

Illinois was the tipping-point-state in the 1900 presidential election.

Bryan had previous lost Illinois to McKinley four years earlier and would later lose the state again in 1908 to William Howard Taft.