Updated October 18, 2026 · polls through October 14, 2026 · House model v0.25
South Dakota House Forecast
‹ See all House racesSouth Dakota elects one representative at large. The COYNTOSS model rates the race Solid R, with a model margin of R+21.2.
Delegation outlook
Solid R for the at-large seat
Forecast summary
- Seats
- 1
- Toss-ups
- 0
- Not rated Solid
- 0
- Districts with polls
- 1 of 1
- Closest district
- SD-01 R+21.2
District map
South Dakota congressional districts
Shaded by forecast rating. Select a district to see its forecast.
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- Solid D
- Likely D
- Lean D
- Toss-up
- Lean R
- Likely R
- Solid R
Boundaries: U.S. Census Bureau, 2026 congressional districts, clipped to the shoreline. Methodology.
The race
Every district in the state, closest model margin first. Bars show each side's published chance of winning.
SD-01 · Open
South Dakota at-large district
Gronli 2.7% · Jackley 97.3% chance of winning
- Model margin
- R+21.2
- Rating
- Solid R
- Polling average
- R+4.0
- Fundamentals
- R+24.8
- Matchup
- Nikki Gronli vs. Marty Jackley
How the forecast is built
Polling blend (published): 17.4%
Fundamentals inputs
- 2024 presidential margin
- R+29.2
- Relative district lean
- R+28.6
- Generic ballot
- D+8.3
- National environment
- D+8.3
- Incumbency
- None
- Candidate
- None
- Fundraising
- None
- Simple fundamentals
- R+20.3
- Full fundamentals
- R+24.8
- Fundamentals blend weight
- 50.0%
- Total uncertainty
- ±11.2 pts
Margins are Democratic minus Republican points, rounded to one decimal. Values are shown as published; the page does not recompute the forecast.
Polling inputs
District polls
1 included survey across 1 district, newest first.
| Field dates | District | Pollster | Sample | Results |
|---|---|---|---|---|
| Aug 26–Aug 30, 2026 | SD-01 | Lake Research Partners | 500.0 LV | D 43.0% · R 47.0% |