South Dakota Republicans swept statewide offices on November 3, keeping control of the governorship, U.S. Senate and U.S. House, while Democrats gained a handful of legislative seats.
Republican Sen. Mike Rounds defeated independent Brian Bengs. Republican Marty Jackley defeated Democrat Nikki Gronli in the open at-large House contest. Gov. Larry Rhoden won a full term against Democrat Dan Ahlers after assuming the office in 2025. Republicans won the remaining statewide offices and retained legislative supermajorities.
Incumbent U.S. Sen. Mike Rounds defeated independent Brian Bengs, receiving approximately 184,600 votes, or 60.5%, compared with 120,500 votes, or 39.5%. There was no major Democratic nominee in the Senate contest.
Republican Marty Jackley won the open at-large U.S. House seat, defeating Democrat Nikki Gronli with about 64% of the vote. Jackley, a former attorney general and U.S. attorney, will succeed retiring Republican Rep. Dusty Johnson.
Gov. Larry Rhoden won his first full term after taking office in early 2025 when former Gov. Kristi Noem joined the Trump administration. Rhoden defeated Democrat Dan Ahlers with roughly 63.5% of the vote.
Other Republican statewide winners included Secretary of State Heather Baxter and candidates for attorney general, auditor, treasurer, commissioner of school and public lands and Public Utilities Commission.
Republicans kept their legislative supermajorities, though Democrats gained a handful of House seats, particularly in Sioux Falls. The net improvement was the first by the party since 2008, leaving Republicans still in a commanding position.
Voters rejected Amendment I, which would have ended the state’s Medicaid expansion if the federal contribution fell below 90%. The vote preserved existing expansion provisions approved by voters in 2022.
Amendment J, specifying U.S. citizenship as a voter qualification, passed. Amendment K, creating a trust for unclaimed property, also won approval. Amendment L, requiring 60% support for future constitutional amendments, was rejected.
About 310,300 ballots were cast from approximately 628,600 registered voters, producing turnout of around 49.4%. The figure was low compared with presidential election participation.
The results reinforced Republican strength in federal and state offices while demonstrating that Democrats could win selected legislative races in the Sioux Falls area. The legislature will continue to be dominated by Republicans in 2027.
Democrats posted gains primarily in Sioux Falls-area legislative districts. Voters rejected Amendment I, which would have ended Medicaid expansion under certain funding conditions, and Amendment L, which proposed a 60% threshold for future constitutional amendments. Amendments J and K, concerning citizenship requirements for voting and an unclaimed property trust, passed. Turnout was approximately 49%.