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South Dakota Senate

  • Mike Rounds (Rep · incumbent)
  • Brian Bengs (Ind)

Republicans are favored, winning in 100 in 100 simulations.

Forecast detail

as of Aug 17, 2026, 3:27 AM UTC

Rating

Favors Rep

Win probability

R 100%

Estimated margin

R+23.9

5th–95th interval

R+35.2 to R+12.4

Win probability over time

Dem win probability Rep win probability Tossup band

Polls

Ind-leaning poll Rep-leaning poll current average: R+20.9

Pollster Dates Sample Results Margin House adj. Source
Brian Bengs (I) vs Mike Rounds (R) · 5 polls
Public Opinion Strategies Jul 6–Jul 9, 2026 500 lv Mike Rounds 56.0% Brian Bengs 33.0% R+23.0 R+21.1 R+1.9 lean removed Source
Public Policy Polling May 29–May 30, 2026 726 rv Mike Rounds 44.0% Brian Bengs 40.0% R+4.0 R+3.8 R+0.2 lean removed Source
Public Policy Polling Feb 17–Feb 18, 2026 685 rv Mike Rounds 47.0% Brian Bengs 35.0% R+12.0 R+11.8 R+0.2 lean removed Source
Public Policy Polling Nov 13–Nov 14, 2025 814 rv Mike Rounds 44.0% Brian Bengs 31.0% R+13.0 R+12.8 R+0.2 lean removed Source
Public Policy Polling Jul 30–Jul 31, 2025 524 lv Mike Rounds 41.0% Brian Bengs 28.0% R+13.0 R+12.8 R+0.2 lean removed Source
Julian Beaudion (D) vs Mike Rounds (R) · 3 polls
Public Policy Polling May 29–May 30, 2026 726 rv Mike Rounds 56.0% Dem 31.0% Source
Public Policy Polling Feb 17–Feb 18, 2026 685 rv Mike Rounds 49.0% Dem 32.0% Source
Public Policy Polling Nov 13–Nov 14, 2025 814 rv Mike Rounds 52.0% Dem 30.0% Source
Brian Bengs (I) vs Julian Beaudion (D) vs Mike Rounds (R) · 1 poll
Public Policy Polling May 29–May 30, 2026 726 rv Mike Rounds 43.0% Brian Bengs 23.0% Dem 18.0% R+20.0 R+19.8 R+0.2 lean removed Source

Dispatches about this race

No dispatches about this race yet.