South Dakota Republicans are casting ballots Tuesday in a gubernatorial primary runoff, choosing between incumbent Gov. Larry Rhoden and businessman Toby Doeden to be their party’s nominee heading into the November general election.
Neither candidate cleared the 35% vote threshold required to clinch the nomination outright during the June 2 primary, forcing a runoff between the two top finishers. Whoever prevails will face Democratic former state Sen. Dan Ahlers in the fall — though the winner enters that race with a clear advantage in a state that hasn’t elected a Democratic governor since the 1970s.
Rhoden became governor in early 2025 after then-Gov. Kristi Noem left office to join President Donald Trump’s Cabinet, with Rhoden moving up from his role as lieutenant governor. The original primary field also included U.S. Rep. Dusty Johnson and state House Speaker Jon Hansen.
Doeden led the June 2 primary with roughly 31% of the vote. Rhoden came in second with about 25%, followed closely by Johnson at 23% and Hansen at approximately 21%.
Two counties are being closely watched as bellwethers on Tuesday. Minnehaha County in eastern South Dakota is home to Sioux Falls, while Pennington County in the west is home to Rapid City. Together, the two counties account for about one-third of the state’s registered Republicans and were central to Doeden’s first-place primary finish.
In the June primary, Doeden narrowly beat Johnson in Minnehaha County and held about a 7-point advantage over Rhoden in Pennington County. Doeden also swept most of the smaller, rural counties across eastern South Dakota.
Rhoden, meanwhile, secured his runoff spot by winning across central and northwestern South Dakota. He posted strong numbers in Meade, Lawrence, and Hughes counties — the latter of which includes Pierre, the state capital. Those three counties together represent about 10% of the state’s registered Republican voters.
Lincoln County, located in the suburbs just south of Sioux Falls, is considered another potential battleground. It ranks as the state’s third-most populous county and is the largest county where neither Doeden nor Rhoden finished first or second in the primary.
Polls close at 7 p.m. local time Tuesday — that’s 8 p.m. Eastern for most of the state, which falls in the Central time zone. Some polling locations operate on Mountain time and will close at 9 p.m. Eastern.
Participation in the runoff is limited to registered Republicans. Those who sat out the June 2 primary are still eligible to vote Tuesday.
As of June 1, South Dakota had approximately 676,000 registered voters. That includes around 322,000 active registered Republicans, 137,000 active registered Democrats, 157,000 active independents or unaffiliated voters, and about 57,000 inactive voters with no party identification.
Roughly 136,000 votes were cast in the Republican gubernatorial primary on June 2. Historical data shows that about 19% of the 2024 primary vote and around 20% of the 2022 primary vote were cast before primary day.
Most counties in South Dakota report results from all voting methods together throughout election night. About four out of five counties include at least some Election Day in-person results alongside mail and early voting totals in their first updates.
During the June 2 primary, results were first reported at 9:01 p.m. Eastern — one minute after polls closed. By 10:57 p.m. ET, roughly half the total vote had been counted, and by 3:36 a.m. ET, nearly all ballots had been tallied.
A winner will only be declared when it becomes clear no remaining uncounted votes could change the outcome. Recounts in South Dakota happen automatically only in the case of a tie. Candidates who lose a statewide race may request a recount if the margin falls within 0.25% of total votes cast.
Tuesday’s runoff comes 98 days before the 2026 midterm elections.
