The 2026 United States Senate election in South Dakota will be held on November 3, 2026, to elect a member of the United States Senate to represent the state of South Dakota. Republican incumbent Mike Rounds is seeking a third term. He is being challenged by Democratic former state trooper Julian Beaudion and independent military officer Brian Bengs.

Primary elections were held on June 2, 2026. Rounds received 75.8% of the vote against minimal opposition and Beaudion ran unopposed for their respective party's nominations. Bengs, the Democratic nominee in the 2022 Senate race, filed to run as an independent. Republicans have not lost a Senate election in South Dakota since 2008.

Republican primary

Candidates

Nominee

Eliminated in primary

  • Justin McNeal, Navy veteran and businessman[2][3]

Endorsements

Mike Rounds
Executive branch officials
Organizations

Fundraising

Campaign finance reports as of March 31, 2026
Candidate Raised Spent Cash on hand
Justin McNeal (R) $1,555 $11 $1,543
Mike Rounds (R) $3,769,823 $2,515,470 $2,936,874
Source: Federal Election Commission[6]

Polling

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Mike
Rounds		 Justin
McNeal		 Undecided
Mason-Dixon Polling & Strategy[7][A] April 7–11, 2026 500 (RV) ± 4.5% 66% 18% 20%
Hypothetical polling

Mike Rounds vs. Kristi Noem

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Mike
Rounds		 Kristi
Noem		 Undecided
Kaplan Strategies[8] June 12, 2023 500 (RV) ± 4.7% 26% 53% 21%

Kristi Noem vs. Dusty Johnson

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Kristi
Noem		 Dusty
Johnson		 Undecided
Kaplan Strategies[8] June 12, 2023 500 (RV) ± 4.7% 54% 23% 23%

Results

Primary results by county:
  Rounds
  •   60–70%
  •   70–80%
  •   80–90%
Republican primary results
Party Candidate Votes %
Republican Mike Rounds (incumbent) 101,471 75.8
Republican Justin McNeal 32,412 24.2
Total votes 133,883 100.0

Democratic primary

Candidates

Nominee

Endorsements

Julian Beaudion
Executive branch officials

Fundraising

Campaign finance reports as of March 31, 2026
Candidate Raised Spent Cash on hand
Julian Beaudion (D) $192,473 $185,994 $6,478
Source: Federal Election Commission[6]

Independents

Candidates

Declared

Fundraising

Campaign finance reports as of March 31, 2026
Candidate Raised Spent Cash on hand
Brian Bengs (I) $564,715 $511,174 $53,540
Source: Federal Election Commission[6]

General election

Predictions

Source Ranking As of
Inside Elections[13] Solid R April 23, 2026
Race To The WH[14] Likely R May 22, 2026
RealClearPolitics[15] Solid R May 19, 2026
Sabato's Crystal Ball[16] Safe R March 4, 2026
The Cook Political Report[17] Solid R April 13, 2026
The Economist[18][b] Likely R May 22, 2026

Endorsements

Brian Bengs
Political parties

Polling

Mike Rounds vs. Julian Beaudion vs. Brian Bengs

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Mike
Rounds (R)		 Julian
Beaudion (D)		 Brian
Bengs (I)		 Undecided
Public Policy Polling (I)[20][B] May 29–30, 2026 726 (RV) ± 3.6% 43% 18% 23% 16%

Mike Rounds vs. Julian Beaudion

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Mike
Rounds (R)		 Julian
Beaudion (D)		 Undecided
Public Policy Polling (I)[20][B] May 29–30, 2026 726 (RV) ± 3.6% 56% 31% 13%
Public Policy Polling (I)[21][B] February 17–18, 2026 685 (RV) ± - 49% 32% 19%
Public Policy Polling (I)[22][B] November 13–14, 2025 814 (RV) ± 3.3% 52% 30% 18%

Mike Rounds vs. Brian Bengs

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Mike
Rounds (R)		 Brian
Bengs (I)		 Undecided
Public Policy Polling (I)[23][B] May 29–30, 2026 726 (RV) ± 3.6% 44% 40% 16%
Public Policy Polling (I)[21][B] February 17–18, 2026 685 (RV) ± - 47% 35% 19%
Public Policy Polling (I)[23][B] November 13–14, 2025 814 (RV) ± 3.3% 44% 31% 25%
Public Policy Polling (I)[24][B] July 30–31, 2025 524 (LV) ± 4.1% 41% 28% 31%

Fundraising

Campaign finance reports as of May 13, 2026
Candidate Raised Spent Cash on hand
Mike Rounds (R)[c] $3,983,663 $3,008,909 $2,657,286
Julian Beaudion (D)[d] $209,807 $206,764 $3,043
Brian Bengs (I)[e] $666,019 $607,867 $58,151
Source: Federal Election Commission[6]

Notes

  1. ↑ Endorsement received after the first round of primary voting took place.
  1. 1 2 3 4 5 6 Key:
    A – all adults
    RV – registered voters
    LV – likely voters
    V – unclear
  2. ↑ The Economist's prediction model uses unconventional terminology. For the purpose of equivalency, their "Very Likely" ratings are formatted as a "Likely" rating while "Likely" ratings are formatted as a "Lean" rating.
  3. ↑ As of June 2, 2026
  4. ↑ As of June 2, 2026
  5. ↑ As of June 18, 2026
  1. ↑ Poll sponsored by South Dakota News Watch and the Chiesman Center for Democracy at the University of South Dakota
  2. 1 2 3 4 5 6 7 8 Poll sponsored by Bengs' campaign

References

  1. ↑ Walsh, Lori; Chilson, Josh (January 22, 2026). "Rounds announces U.S. Senate reelection bid". SDPB. Retrieved January 22, 2026.
  2. ↑ "Campaign roundup: Republican announces for US Senate, other races grow, polls and money info emerge". South Dakota Searchlight. November 1, 2025. Retrieved November 2, 2025.
  3. ↑ staff, Dakota News Now (April 5, 2026). "Justin McNeal to appear on ballot for US Senate in June 2 primary". Dakota News Now. Retrieved April 6, 2026.
  4. ↑ Dakota War College (July 21, 2025). "After GOP pokes at him on Facebook, President Trump has high and undenaible praise for Senator Rounds". Dakota War College. Retrieved July 21, 2025.
  5. ↑ "Thank You for Supporting Pro-Israel Incumbent Members of Congress". AIPAC Political Portal. Retrieved April 30, 2026.
  6. 1 2 3 4 "2026 Election United States Senate – South Dakota". fec.gov. Federal Election Commission. Retrieved July 21, 2025.
  7. ↑ Rifaat, Alexander (April 20, 2026). "Poll: Johnson widens lead in SD GOP governor race". South Dakota News Watch. Retrieved April 20, 2026.
  8. 1 2 Sneve, Joe (June 13, 2023). "Pollster says Noem strongest GOP official in South Dakota. But where's Marty Jackley?". The Dakota Scout. Retrieved December 24, 2025.
  9. ↑ Dausch, Dominik (April 10, 2025). "Democrat Julian Beaudion announces US Senate run for Republican Mike Rounds' seat in 2026". Argus Leader. Retrieved April 30, 2025.
  10. ↑ Langer, Reed (April 4, 2026). "Julian Beaudion to appear on ballot as Democratic U.S. Senate candidate". Kota Territory. Retrieved April 5, 2026.
  11. ↑ Burns, Krista (June 5, 2026). "President Biden Endorses Dan Ahlers, Julian Beaudion, and Nikki Gronli for Governor, U.S. Senate, & U.S. House". South Dakota Democratic Party. Retrieved June 5, 2026.
  12. ↑ Dausch, Dominik (April 30, 2025). "Former Democrat Brian Bengs launches independent bid for Mike Rounds' Senate seat in 2026". Argus Leader. Retrieved April 30, 2025.
  13. ↑ "Senate Ratings". Inside Elections. Retrieved January 14, 2025.
  14. ↑ "2026 Senate Forecast". Race to the WH. Retrieved March 19, 2025.
  15. ↑ "Battle for the Senate 2026". RealClearPolitics. Retrieved May 24, 2026.
  16. ↑ "2026 Senate ratings". Sabato's Crystal Ball. Retrieved February 13, 2025.
  17. ↑ "2026 CPR Senate Race Ratings". Cook Political Report. Retrieved April 13, 2025.
  18. ↑ "2026 Senate Forecast". The Economist. Retrieved May 24, 2026.
  19. ↑ "Candidates". Forward Party. Retrieved April 8, 2026.
  20. 1 2 "Hotline's Wake-Up Call!". National Journal. Retrieved June 8, 2026.
  21. 1 2 "Hotline's Wake-Up Call!". National Journal. Retrieved June 6, 2026.
  22. ↑ "Hotline's Wake-Up Call!". National Journal. Retrieved December 4, 2025.
  23. 1 2 "Hotline's Wake-Up Call!". National Journal. Retrieved June 8, 2026.
  24. ↑ Nicholas Anastácio [@NenoNicolosio] (October 30, 2025). "A little ol' #SDSEN poll from @njhotline: A Public Policy Polling survey conducted for 2022 nominee Brian Bengs (I) found Sen. Mike Rounds (R) ahead of him in a head-to-head race Rounds 41% Bengs 28% Undecided 31% July 30–31; 552 LVs; +/-4.1%" (Tweet). Retrieved December 4, 2025 – via X (formerly Twitter).
Official campaign websites
source: https://en.wikipedia.org/wiki/2026_United_States_Senate_election_in_South_Dakota