South Dakota Senate
2026 forecast. Updated October 22, 2026, 09:28 UTC
35 of 35 seats are up in 2026. Democrats are forecast to hold 3 seats after November (80% range 1–5) and Republicans 32 (30–34). In 2 seats a Democrat or Republican faces only independents or minor-party candidates and is counted as winning; in 2018 to 2024 such candidates lost about 3% of the time, mostly to sitting independents.
Initial version. This model was tested on every state legislative election from 1994 to 2024 before publication, forecasting each as if it had not happened. It beat the simple rule “the party that holds the seat keeps it”, and its chamber seat counts were off by 2.9 seats on average (target: under 3). Districts with no two-party race last time are read from their own presidential vote, a change tested in advance that cut their average error from 17 to 13 points. It missed one of its five accuracy targets: in 2024, the calmest year on record, its ranges were wider than they needed to be (92% of results fell inside its 80% ranges; target: at most 88%). Treat the ranges as cautious. The full test record and code.
Go to a district
Shaded by the chance of a Democratic win; pale dashed chips are not up in 2026.
Districts
Chance: of a Democratic win (in a district electing several members, of Democrats winning at least half its seats). Source: where the candidate list came from.
| District | Status | Candidates | Democratic chance | Source |
|---|---|---|---|---|
| 1 | Decided: only a Republican is running | Michael H. Rohl (R) | aggregator (The Ballot Brief) | |
| 2 | Decided: only a Republican is running | John Sjaarda (R) | aggregator (The Ballot Brief) | |
| 3 | Decided: only a Republican is running | Katherine "Katie" Washnok (R) | aggregator (The Ballot Brief) | |
| 4 | Decided: only a Republican is running | Stephanie Sauder (R) | aggregator (The Ballot Brief) | |
| 5 | Decided: only a Republican is running | Glen A. Vilhauer (R) | aggregator (The Ballot Brief) | |
| 6 | Decided: only a Republican is running | Ernie Otten (R) | aggregator (The Ballot Brief) | |
| 7 | Decided: only a Republican is running | Tim Reed (R) | aggregator (The Ballot Brief) | |
| 8 | No Democrat running: counted Republican | Clint Hoyer (independent), Casey Crabtree (R) | aggregator (The Ballot Brief) | |
| 9 | Decided: only a Republican is running | Joy Hohn (R) | aggregator (The Ballot Brief) | |
| 10 | Forecast | Liz Larson (D), Michael Dupic (R) | 99% | aggregator (The Ballot Brief) |
| 11 | Forecast | Aaron Matson (D), Chris Karr (R) | 3% | aggregator (The Ballot Brief) |
| 12 | Forecast | Joe Zweifel (D), Kari Shanard-Koenders (R) | 17% | aggregator (The Ballot Brief) |
| 13 | Decided: only a Republican is running | Sue Peterson (R) | aggregator (The Ballot Brief) | |
| 14 | Decided: only a Republican is running | Larry P. Zikmund (R) | aggregator (The Ballot Brief) | |
| 15 | Forecast | Erik Muckey (D), Brenda Lawrence (R) | 77% | aggregator (The Ballot Brief) |
| 16 | Decided: only a Republican is running | Kevin D. Jensen (R) | aggregator (The Ballot Brief) | |
| 17 | Decided: only a Republican is running | Sydney Davis (R) | aggregator (The Ballot Brief) | |
| 18 | Forecast | Kay Swihart (D), Lauren Nelson (R) | 5% | aggregator (The Ballot Brief) |
| 19 | Forecast | Russell E. Graeff (D), Kyle Schoenfish (R) | 2% | aggregator (The Ballot Brief) |
| 20 | Decided: only a Republican is running | Paul Miskimins (R) | aggregator (The Ballot Brief) | |
| 21 | Forecast | Dan Andersson (D), Mykala Voita (R) | <1% | aggregator (The Ballot Brief) |
| 22 | Decided: only a Republican is running | Brandon R. Wipf (R) | aggregator (The Ballot Brief) | |
| 23 | Decided: only a Republican is running | Mark Lapka (R) | aggregator (The Ballot Brief) | |
| 24 | Decided: only a Republican is running | Jim Mehlhaff (R) | aggregator (The Ballot Brief) | |
| 25 | No Democrat running: counted Republican | Bryan J. Breitling (independent), Bart Sample (R) | aggregator (The Ballot Brief) | |
| 26 | Forecast | Shawn Bordeaux (D), Rebecca Reimer (R) | 10% | aggregator (The Ballot Brief) |
| 27 | Forecast | Celestine Stadnick (D), Peri Pourier (independent), Anthony Kathol (R) | 75% | aggregator (The Ballot Brief) |
| 28 | Decided: only a Republican is running | Sam Marty (R) | aggregator (The Ballot Brief) | |
| 29 | Decided: only a Republican is running | William J. Meirose (R) | aggregator (The Ballot Brief) | |
| 30 | Decided: only a Republican is running | Amber Hulse (R) | aggregator (The Ballot Brief) | |
| 31 | Decided: only a Republican is running | Randy Deibert (R) | aggregator (The Ballot Brief) | |
| 32 | Forecast | Jeff Shelton (D), Helene Duhamel (R) | 10% | aggregator (The Ballot Brief) |
| 33 | Forecast | Christopher Baumgartner (D), David Johnson (R) | 6% | aggregator (The Ballot Brief) |
| 34 | Forecast | Michael Calabrese (D), Taffy Howard (R) | 2% | aggregator (The Ballot Brief) |
| 35 | Decided: only a Republican is running | Greg Blanc (R) | aggregator (The Ballot Brief) |