SD Senate forecast
Safe Rep
Polls close . Statewide at 7:00 PM local time: 8:00 PM ET in most of South Dakota, 9:00 PM ET in the Mountain-time west
Rounds 93% chance
- Brian Bengs (I)0% past 7 days6%
- Mike Rounds (R)-2% past 7 days93%
Chance over time
- Bengs6%
- Rounds93%
Chance over time, past month: Bengs from 5% to 6%; Rounds from 95% to 93%.
| Date | Bengs | Rounds |
|---|---|---|
| Sep 22, 2026 | 5% | 95% |
| Sep 29, 2026 | 5% | 94% |
| Oct 7, 2026 | 5% | 93% |
| Oct 14, 2026 | 5% | 93% |
| Oct 21, 2026 | 6% | 92% |
Projected margin
Most likely Rounds by 0–10 · 8 in 10: Rounds +27.3 to Rounds +0.1
| Margin | Chance |
|---|---|
| Rounds by 45+ | <1% |
| Rounds by 40–45 | 1% |
| Rounds by 35–40 | 1% |
| Rounds by 30–35 | 6% |
| Rounds by 25–30 | 3% |
| Rounds by 20–25 | 7% |
| Rounds by 15–20 | 14% |
| Rounds by 10–15 | 20% |
| Rounds by 0–10 | 38% |
| Bengs wins | 9% |
Helm simulation
Decides Senate control in 1 of 100 simulations.
In simulated elections where Bengs wins, Democrats win the Senate in 87 of 100. Where Rounds wins, in 63 of 100.
Context
- Seat held by Republicans.
More in South Dakota
Ballot measures
- South Dakota passes ballot measure banning noncitizens from voting?Yes 91%