South Dakota · 2026 forecast · Updated Oct 16, 2026

Who will control the South Dakota State Senate?

All 35 seats are on the ballot. 18 seats make a majority. 24 make the two-thirds supermajority that can override a veto.

Republicans are very likely to control the South Dakota State Senate (>99%).

Democrats

<1%

chance of control

Republicans

>99%

Avg. D seats: 4.380% range 3–6
Avg. R seats: 30.780% range 29–32
Now: 3 D · 32 R35 up this year

Republican supermajority now (32 of 35 seats; 24 needed for two-thirds): >99% chance it holds · <1% chance it's broken.

3 D nowMarks: two-thirds supermajority for each party32 R now

Republicans are very likely to control the South Dakota State Senate (>99%).

Democrats

<1%

chance of control

Republicans

>99%

Avg. D seats: 4.080% range 2–6
Avg. R seats: 31.080% range 29–33
Now: 3 D · 32 R35 up this year

Republican supermajority now (32 of 35 seats; 24 needed for two-thirds): >99% chance it holds · <1% chance it's broken.

3 D nowMarks: two-thirds supermajority for each party32 R now

Solid D
Likely D
Lean D
Toss-up
Lean R
Likely R
Solid R

Race ratings

All 35 races, grouped by the leader's chance of winning.

1 seat projected to flip: 1 R→D.

No seat is projected to change parties. 2 more are toss-ups that could change parties (flip risk).

Solid D2

Likely D0

Lean D2

Toss-up0

Lean R2

Likely R1

LD-32

Solid R28

Show 22 more

Solid D0

Likely D2

Lean D0

Toss-up2

Lean R3

Likely R1

LD-34

Solid R27

Show 21 more

Columns follow the chance of winning: Toss-up 40–60%, Lean 60–80%, Likely 80–95%, Solid 95%+. The square shows who holds the seat now (■ Democrats, ■ Republicans). flip: projected to change parties, in the color of the party favored to gain it. risk: a toss-up (40–60%) that could change parties. Underlined: two candidates of one party in November. Faded: no major-party opponent.

The map

Each district colored by the leader's chance of winning. Hover for details; click for the race.

South Dakota

Sioux Falls

Solid D
Likely D
Lean D
Toss-up
Lean R
Likely R
Solid R
Projected flip (stripes: party holding it now)

Seats to watch

The closest races (Lean or Toss-up, Horizon), and the seats most likely to change parties.

Closest races

LD-26Shawn BordeauxRebecca Reimer63%Rep.71%Rep. LD-12Joe ZweifelKari Shanard-KoendersD flipFlip risk70%Dem.56%Dem. LD-11Aaron MatsonChris Karr70%Rep.65%Rep. LD-27Celestine StadnickAnthony KatholFlip risk78%Dem.56%Dem.

Most likely to flip

LD-12Joe ZweifelKari Shanard-KoendersD flipFlip risk70%to flip56%to flip LD-26Shawn BordeauxRebecca Reimer37%to flip29%to flip LD-11Aaron MatsonChris Karr30%to flip35%to flip LD-27Celestine StadnickAnthony KatholFlip risk22%to flip44%to flip LD-32Jeff SheltonHelene Duhamel16%to flip38%to flip LD-34Michael CalabreseTaffy Howard4%to flip6%to flip LD-15Erik MuckeyBrenda Lawrence3%to flip15%to flip LD-18Kay SwihartLauren Nelson2%to flip3%to flip LD-10Liz LarsonMichael Dupic<1%to flip5%to flip LD-33Christopher BaumgartnerDavid Johnson<1%to flip1%to flip

How the odds have moved

Chance of winning control, by forecast date.

Updated nightly. Each day is the current model run on the polls that had ended by then (how).

Every outcome we simulated

Democratic seats across 40,000 simulations. Darker bars: the middle 80%.

Every race

35 races, 23 without a contest between the major parties.

35 races

District	Candidates	Chance of winning (D · R)	Avg. margin	Rating	Lean	Polls
LD-1	● No Democrat● Michael RohlINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+20	—
LD-2	● No Democrat● John Sjaarda	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+26	—
LD-3	● No Democrat● Katherine Washnok	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+27	—
LD-4	● No Democrat● Stephanie SauderINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+53	—
LD-5	● No Democrat● Glen VilhauerINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+41	—
LD-6	● No Democrat● Ernie OttenINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+31	—
LD-7	● No Democrat● Tim ReedINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+9	—
LD-8	● No Democrat● Casey CrabtreeINCAlso: Clint Hoyer (I)	No Democrat on the ballotNo Democrat on the ballot	—	Solid R (no Democrat)Solid R (no Democrat)	R+35	—
LD-9	● No Democrat● Joy HohnINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+23	—
LD-10	● Liz LarsonINC● Michael Dupic	>99%<1% 95%5%	D+26.7D+16.7	Solid DLikely D	D+9	—
LD-11	● Aaron Matson● Chris KarrINC	30%70% 35%65%	R+3.8R+3.7	Lean RLean R	R+12	—
LD-12D flipFlip risk	● Joe Zweifel● Kari Shanard-Koenders	70%30% 56%44%	D+3.7D+1.5	Lean DToss-up	R+5	—
LD-13	● No Democrat● Sue PetersonINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+12	—
LD-14	● No Democrat● Larry ZikmundINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+3	—
LD-15	● Erik Muckey● Brenda Lawrence	97%3% 85%15%	D+15.2D+10.4	Solid DLikely D	D+3	—
LD-16	● No Democrat● Kevin D. JensenINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+45	—
LD-17	● No Democrat● Sydney DavisINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+17	—
LD-18	● Kay Swihart● Lauren NelsonINC	2%98% 3%97%	R+15.8R+19.9	Solid RSolid R	R+27	—
LD-19	● Russell Graeff● Kyle SchoenfishINC	<1%>99% <1%>99%	R+42.5R+49.7	Solid RSolid R	R+55	—
LD-20	● No Democrat● Paul MiskiminsINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+44	—
LD-21	● Dan Andersson● Mykala VoitaINC	<1%>99% <1%>99%	R+40.5R+47.8	Solid RSolid R	R+53	—
LD-22	● No Democrat● Brandon WipfINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+41	—
LD-23	● No Democrat● Mark LapkaINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+61	—
LD-24	● No Democrat● Jim MehlhaffINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+40	—
LD-25R vs R	● No Democrat● Tom PischkeINCAlso: Bryan Breitling (I), Bart Sample (R)	Republicans only in NovemberRepublicans only in November	—	Solid R (R vs R)Solid R (R vs R)	R+36	—
LD-26	● Shawn Bordeaux● Rebecca Reimer	37%63% 29%71%	R+2.5R+5.6	Lean RLean R	R+11	—
LD-27Flip risk	● Celestine Stadnick● Anthony KatholAlso: Peri Pourier (I)	78%22% 56%44%	D+5.7D+1.5	Lean DToss-up	R+4	—
LD-28	● No Democrat● Sam MartyINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+39	—
LD-29	● No Democrat● William J. Meirose	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+53	—
LD-30	● No Democrat● Amber HulseINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+47	—
LD-31	● No Democrat● Randy DeibertINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+34	—
LD-32	● Jeff Shelton● Helene DuhamelINC	16%84% 38%62%	R+8.1R+2.8	Likely RLean R	R+9	—
LD-33	● Christopher Baumgartner● David Johnson	<1%>99% 1%99%	R+28.5R+27.2	Solid RSolid R	R+33	—
LD-34	● Michael Calabrese● Taffy HowardINC	4%96% 6%94%	R+13.2R+15.3	Solid RLikely R	R+22	—
LD-35	● No Democrat● Greg BlancINC	Republican unopposedRepublican unopposed	—	Uncontested RUncontested R	R+34	—

Lean: how much more Democratic (D+) or Republican (R+) the place voted for president than the nation (2024 weighted 75%, 2020 25%). Ratings follow the chance of winning: Toss-up 40–60%, Lean 60–80%, Likely 80–95%, Solid 95%+. INC = incumbent running. D flip / R flip: another party is favored (60% or more) over the party holding the seat now (hover for the chance it changes parties); Flip risk: the seat is a toss-up (40–60%). Badges mark election rules (hover or long-press for details): RCV = ranked-choice voting; Top two / Top four = the leading primary finishers advance; All-party = every candidate on one November ballot; TBD = no candidate list yet, forecast for the seat's party against a generic challenger.