1904 United States presidential election in South Dakota

The 1904 United States presidential election in South Dakota took place on November 8, 1904. All contemporary 45 states were part of the 1904 United States presidential election. Voters chose four electors to the Electoral College, which selected the president and vice president.

South Dakota was won by the Republican nominees, incumbent President Theodore Roosevelt of New York and his running mate Charles W. Fairbanks of Indiana. They defeated the Democratic nominees, former Chief Judge of New York Court of Appeals Alton B. Parker and his running mate, former US Senator Henry G. Davis of West Virginia. Roosevelt won the state by a margin of 49.42%.

Roosevelt's win in South Dakota was the first time any presidential candidate swept every county in the state, which has only occurred once since, with Dwight D. Eisenhower's win in 1952.

With 71.09% of the popular vote, South Dakota would be Roosevelt's fourth strongest victory in terms of percentage in the popular vote after Vermont and South Dakota's neighboring states North Dakota and Minnesota. As of 2024, this is the best performance by any candidate in the state.