Since achieving statehood in 1889, South Dakotans have voted on 366 statewide ballot measures. Voters approved 160 (43.7%) and rejected 206 (56.3%).

In South Dakota, most measures are placed on the ballot by the South Dakota State Legislature or through a successful citizen initiative. The Legislature voted to refer 233 measures to the state ballot, while 131 citizen initiatives made the ballot. Referrals by the state legislature were approved more often than citizen initiatives. Out of the legislative referrals, 118 (50.64%) were approved by voters, and 115 were rejected. Out of the citizen initiatives, 40 (30.53%)  were approved by voters, and 91 were rejected.

Additionally, two measures in 1889—the first ballot measures decided in South Dakota—were placed on the ballot by a constitutional convention. Both of these measures—one which ratified the constitution, and the other that established the prohibition on alcohol—were approved by voters.

There have been nine different types of ballot measures in South Dakota. Legislatively referred constitutional amendments have appeared on the ballot the most number of times (230). Besides the two approved constitutional convention referrals, legislatively referred constitutional amendments had the highest approval rating, with 51.3% approved. Indirect initiated state statutes had the lowest success rate, with seven measures (24.14%) approved and 22 (75.86%) defeated.

South Dakota ballot measures addressed 131 unique topics. The most common topic was public education funding, which included 38 measures. Other common topics included business regulations (24 measures), property taxes (24 measures), and state legislative authority (21 measures).

Below is a selection of notable and unique ballot measures in South Dakota’s history. For a more detailed list, see here.

• South Dakota was the first state to have voters decide on the initiative and referendum process. In 1898, voters approved an amendment establishing the initiative and referendum process in the state.

• South Dakota voters decided on women’s suffrage seven times—the most of any state. The first six times, voters rejected women’s suffrage amendments, with the first appearing on the ballot in 1890. Voters finally approved an amendment granting women the right to vote in 1918.

• Voters approved a right-to-work measure in 1946, which included the right-to-work in the state Bill of Rights.

• In 1972, voters decided on an amendment that provided for the right of citizens to initiate constitutional amendments and constitutional conventions, nor just statutes.

• Voters decided five measures related to gaming and wagering proceeds to go to the historic restoration and preservation of Deadwood, a town known for its gold rush history. Voters approved the first amendment authorizing gambling in Deadwood in 1988, and most recently approved legalizing sports betting in Deadwood in 2020.

• Voters decided on marijuana six times in the state. Voters approved medical marijuana in the state in 2020, after rejecting it twice in 2006 and 2010. In 2020, voters also approved legalizing recreational marijuana. However, this measure was overturned in 2021, with a Circuit Court ruling that the measure violated the state’s single subject law. The next two attempts to legalize marijuana in the state in 2022 and 2024 were rejected by voters.

• Voters approved an amendment expanding Medicaid in 2022. This amendment required the state to expand Medicaid to adults between 18 and 65 with incomes below 138% of the federal poverty level.

Of the 366 measures in South Dakota, 12 were decided by less than a percentage point.

The measure with the closest margin was Amendment A in 1984, which would have combined the duties of the state treasurer and the commissioner of school and public lands. The measure was defeated, with 49.95% voting in favor of the measure and 50.05% voting against it, resulting in a margin of 0.10 percentage points.

The measure with the widest margin was Referred Law 5 in 1922, which would have relocated the state university from Vermillion to Sioux Falls. The measure was defeated with 7.71% voting in favor of the measure, and 92.29% voting against it, resulting in a margin of 84.58 percentage points.

The decade with the most ballot measures was the 1910s, which featured 55 ballot measures. Of these, 23 were approved, and 32 were defeated. In the 1880s, two ballot measures were approved. Besides the 1880s, the decade with the highest approval rate was the 1900s, which featured 18 measures—13 were approved, and five were defeated. The decade with the lowest approval rating was the 1920s. In the 1920s, 23 ballot measures were considered, with two being approved and 21 being defeated.

The inventory of South Dakota statewide ballot measures is part of Ballotpedia’s Historical Ballot Measure Factbook, which will document nearly 200 years of direct democracy in the United States. This ongoing research effort will provide an unparalleled resource for researchers, reporters, and the voting public on how ballot measures have evolved, the issues they’ve covered, and the role they have played in our civic life.