2026 state legislative forecast
South Dakota Senate forecast
Republicans win control of the South Dakota Senate in nearly every one of 2,000 simulations, against a Republican majority today. All 35 seats are on the 2026 ballot; 2 races are within a 35 to 65 split.
Chance of control
<1%D>99%R
Democratic seats, 80% range
5 to 8Median 6 · 18 for a majority
Favored to flip
4to D0to R
After 2024: 3 D, 32 R
Environment
D +14.6Shift from the 2024 presidential vote
South Dakota Senate map
Safe DLean DToss upLean RSafe R
District shapes are estimated from where each district's voters live in the precinct returns, not drawn from the official boundary files.
Pick a district
Hover the map for the odds in any district. Click one to pin it here and find it in the table below.
Every seat
Average 6 D to 29 RSafe DLean DToss upLean RSafe R
Democratic seats across 2,000 simulations
Every Senate district
| District | Last winner | 2026 nominees | 2024 lean | Forecast | Dem win | Rating |
|---|---|---|---|---|---|---|
| 11 | Chris Karr 2024 | Aaron Matson vs Chris Karr | R +9.8 | D +0.8 | 55% | Toss up |
| 26 | Tamara Grove 2024 | Shawn Bordeaux vs Rebecca Reimer | R +12.8 | D +0.9 | 52% | Toss up |
| 34 | Taffy Howard 2024 | Michael Calabrese vs Taffy Howard | R +16.5 | R +4.0 | 26% | Lean R |
| 18 | Lauren Nelson 2024 | Kay Swihart vs Lauren Nelson | R +26.6 | R +6.2 | 19% | Likely R |
| 12 | Arch Beal 2024 | Joe Zweifel vs Kari Shanard-Koenders | R +5.3 | D +6.3 | 83% | Likely D |
How this is built
Each district starts from its 2024 presidential vote, read off the precincts that voted in it, and moves with the state's 2026 House forecast and the national generic ballot. Half of what the last legislative winner ran ahead of the district carries over, 2026 primary turnout moves districts where it is posted, and district and statewide legislative polls count by recency and sample. A seat with no candidate from one party is called for the other. 2,000 simulations share a national, a state and a district shock. The map's district shapes are estimated from where each district's voters are in the precinct returns. All chambers.