1900 United States presidential election in Idaho

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

Idaho was won by the Democratic nominees, William Jennings Bryan of Nebraska and his running mate Adlai Stevenson I of Illinois. Bryan and Stevenson defeated the Republican nominees, incumbent president William McKinley of Ohio and his running mate Theodore Roosevelt of New York. Bryan won the state by a narrow margin of 3.83%.

Bryan had previously defeated McKinley in Idaho four years earlier. He would later lose the state to William Howard Taft in 1908. As of the 2020 election, this is the last election in which the Republican candidate won the presidency without Idaho. This is one of two elections where the Republican candidate won without the state, the other being four years prior in 1896, and by extension marks the only time that a Republican has won reelection without the state.