2026 forecast · South Dakota at-large

Marty Jackley is all but certain to win South Dakota's at-large District.

Nikki Gronli vs Marty Jackley, an open seat. The model has Jackley ahead by 17.7 points, winning 99 percent of 2,000 simulated elections.

Safe RModel R +17.7Polls R +0.0Updated October 22, 2026
Nikki Gronli
Democrat
41.1%
158,613 projected votes
Marty Jackley
Republican
58.9%
226,904 projected votes
99%Jackley
1%Gronli
Jackley all but certainEach square is one simulated election night, Jackley wins about 99 of 100
RatingSafe R99% chance for Jackley
Model marginR +17.7Polls R +0.0
80 percent rangeR +8.7 to R +26.62,000 simulations
Projected votes385,517Jackley 58.9%

The district map

Every district in the state, shaded by its rating

South Dakota districts

1 districts
Safe DLikely DLean DToss upLean RLikely RSafe R

Vote share

Each candidate's projected share and the range of 80 percent of simulations

Nikki GronliDemocrat · 1% to win
41.1%
Marty JackleyRepublican · 99% to win
58.9%

Scale runs from 25 to 75 percent. The dot is the forecast, the band is the 80 percent range and the brighter tick marks 50 percent.

Projected district vote

385,517 votes
CandidateVotesShare
Marty Jackley R226,90458.9%
Nikki Gronli D158,61341.1%
Total385,517100%

Each candidate's expected vote in the On Point simulation, at the forecast's projected turnout.

The trend

Each side's chance of winning over the forecast's recent updates

0%25%50%75%100%1% Gronli99% Jackley15 updates agoToday

Polling

Every poll in the average, and how the model reads it

The South Dakota governor polling average
30%35%40%45%50%55%60%Sep 2Sep 9Sep 16Sep 23Sep 30Oct 7Oct 1439.2Ahlers49.3Rhoden
The line is the On Point average: a robust LOWESS fit through the polls, weighted by recency, sample, voter screen and pollster grade, refit three times so outliers count for lessDot size is each poll's weight todayHover or use the arrow keys to read any day
What moves the average today
Concord Public Opinion Partners (D)Oct 8 · 400 LV · NR70%Rhoden +10.0
Lake Research Partners (D)Aug 30 · 500 LV · NR23%Rhoden +7.0
Mason-Dixon for South Dakota News Watch and USD Chiesman CenterOct 14 · 500 LV · D-7.7%Rhoden +20.0

This is the same On Point polling average as the full average page. The forecast reads the polls through its own Election Day projection, shown as the On Point average in the table below, and blends it with partisan lean and fundamentals.

Polls of the race

Full average
PollsterSampleAgeMargin
On Point averageWeighted averageR +0.0

Each margin is the poll as the pollster published it. The forecast counts every poll after its house effect and the undecided split, which is what the trail above shows; hover a margin for the counted value. Lean R and Lean D mark partisan leaning firms.

Model margin
Jackley +17.7
Chance of winning
Nikki Gronli1%
Marty Jackley99%
Simulated vote
Nikki Gronli41.1%
Marty Jackley58.9%
How the model gets there
Partisan leanD +29.0
FundamentalsR +17.7
With pollsR +17.1
Early vote turnoutR +0.6
With early voteR +17.7

Read from 0 ballots cast so far in South Dakota, against the party mix the forecast expected of them, with similar states and primary turnout. Early vote tracker

How we got here

From the state's partisan lean to the forecast, one stage at a time

D +35R +35Partisan leanthe state's baselineD +29.0Fundamentalsapproval, economy, candidatesR +17.7With pollsaverage R +0.0R +17.1With early voteturnout so farR +17.7
Methodology
Every county is rebuilt by simulating voters going to the polls, 2,000 times, from On Point Polling survey data, past results, and the polling average. How the model works.