2026 midterm forecast
South Dakota House
The at-large House seat
Forecast published October 30, 2026 · Election Day is November 3, 2026
Foresight forecast
Chance to win the seat
>99%
Marty J. Jackley (R)
Seat margin
R+26.0
Statewide House vote
R+25.2
>99% R · ±13 points, 95% range
Statewide two-party House vote · 16% of likely voters undecided
Key insights
South Dakota's at-large House seat should stay in Republican hands
South Dakota has one House seat, and Republicans, who hold it, lead by 26.0 points in the at-large district. Democrats have a long way to go.
Men favor Republicans by 41.7 points and women by just 8.5. Age matters too, as voters 18–29 lean Republican by only 5.7 points while those 45–64 favor them by 30.9.
The race
South Dakota elects one member of the U.S. House, at large. The seat is held by Dusty Johnson (R).
On the ballot: Nicole Gronli (D) vs. Marty J. Jackley (R).
District by district
Foresight's forecast for each district, as drawn for 2026.
| District | Candidates | Held by | Margin | Chance | Rating |
|---|---|---|---|---|---|
| SD-AL | Nicole Gronli (D) vs. Marty J. Jackley (R) | R | R+26.0 | >99% R | Safe R |
Vote by group
Own vote of likely voters in each group, two-party margin.DemocratsRepublicans
Age
Gender
Education
Area
By county
Foresight's margin in each county.
County margins in points. Faded: fewer than 5 respondents. Blank: no respondents.
How this forecast is made: read the method.