South Dakota's electoral votes in U.S. presidential elections 1892-2020

South Dakota has taken part in all U.S. presidential elections since 1892, voting for the nationwide winner in 19 out of 33 elections, which gives a success rate of 59 percent. In these 32 elections, South Dakota has voted for the Republican nominee 28 times, including all elections since 1968. The only times where South Dakota voted Democrat were for William Jennings Bryan in 1896, FDR in both 1932 and 1936, and then for LBJ in his landslide victory in 1964; there was also one occasion where South Dakota voted for a third party nominee, this was in 1912 when it voted for former-president Theodore Roosevelt as he ran on the ticket of the Progressive Party. In the 2020 election, Donald Trump won the popular vote in the Mount Rushmore State by a comfortable 26 percent margin.

As of 2020, no U.S. president has come from South Dakota, although both Democratic nominees in the 1968 and 1972 elections, former vice president Hubert Humphrey and George McGovern respectively, were born in South Dakota; despite this, Richard Nixon carried South Dakota on both occasions. For most of its history, South Dakota was allocated four electoral votes; this number did peak at five votes between 1912 and 1928, however it has been at just three since 1984, which is the lowest possible number.