South Dakota

U.S. Senate · South Dakota

Election day November 3, 2026 · forecast of October 15, 2026

Our forecast gives another party a 58% chance of winning, with an average lead of 10.4 points.

Toss-up. Chance of a final gap under 5 points: 30%.

Projected vote share

Projection by party

Other 46.5%
Republican 43.9%

Mike Rounds, incumbent
Democrat 9.6%

Compared with the average

	Other	Republican	Democrat
South Dakota	46.5%	43.9%	9.6%
National averageUnited States	4.0%+42.5	48.7%−4.8	47.3%−37.7

Simple average of the 100 districts, not weighted by population.

Projection track

How the projection has moved

Polls in this district

9 polls

Pollster	Field dates	Sample	Population	Topline	Source
Zenith Research	24–Sep 27, 2026	500	likely voters	Republican 53 Independent and others 47	See the poll
Public Policy Polling	8–Sep 9, 2026	629	registered voters	Republican 45 Independent and others 42	See the poll
Lake Research Partners	26–Aug 30, 2026	500	likely voters	Independent and others 51 Republican 41	See the poll
Impact Research	13–Aug 17, 2026	500	likely voters	Republican 44 Independent and others 44	See the poll
Public Opinion Strategies National Republican Senatorial Committee	6–Jul 9, 2026	500	likely voters	Republican 56 Independent and others 33	See the poll
Public Policy Polling	29–May 30, 2026	726	registered voters	Republican 43 Independent and others 23 Democrat 18	See the poll
Public Policy Polling	17–Feb 18, 2026	685	registered voters	Republican 49 Democrat 32	See the poll
Public Policy Polling	13–Nov 14, 2025	814	registered voters	Republican 52 Democrat 30	See the poll
Public Policy Polling	30–Jul 31, 2025	552	registered voters	Republican 41 Independent and others 28	See the poll

Each poll as the pollster published it; these are not the Vote-Scope projection. When a pollster tests several ballots (with or without a given candidate), each one is shown as a scenario.

Current member

Mike Rounds · Republican

Primary results

Held June 2, 2026 · Official source

Republican primary	Mike Rounds	75.8%	101,284 votes

Who's running

The candidates

Candidates for the upcoming election.

Republican Incumbent

Mike Rounds
source
Other Challenger

Bengs, Brian

General-election qualification remains to be verified.

Other races in the region

Party ahead and how sure the projection is.

Alaska Republican, toss-up
Alabama Republican, safe seat
Arkansas Republican, safe seat
Colorado Democrat, safe seat
Delaware Democrat, safe seat
Georgia Democrat, competitive

Watch list

The tightest races

The smallest projected gaps between the top two.

Forecast updated: October 15, 2026