Voters in the US state of Ohio are set to go to the polls in the state’s primaries, where they will pick candidates for several key positions in the upcoming midterm elections in November.

The outcomes of several races in the Midwestern state could have important implications for the crucial midterms, widely seen as a referendum on United States President Donald Trump’s second term and as a vote that will decide which party controls Congress for the remainder of his time in office.

When does voting take place, which races are being watched, and who are some of the main candidates? We answer those questions and more in this brief explainer.

When is the Ohio primary?

The Ohio primary will take place on Tuesday, May 5, 2026.

When do polls open and close?

Polls will open on Election Day at 6:30am local time (10:30 GMT) and close at 7:30pm (23:30 GMT).

What’s on the ballot?

Voters will have the chance to choose candidates in primaries for races for the US Senate, US House, governor, attorney general, secretary of state, treasurer, state supreme court, state senate and state house.

Which races are front and centre?

The special election for one of Ohio’s two US Senate seats and the race to replace Republican Governor Mike DeWine have attracted the most attention due to their ties to national politics.

In the gubernatorial race, Trump-backed former presidential candidate and tech entrepreneur Vivek Ramaswamy is facing off against internet personality Casey Putsch for the Republican nomination.

That race could test how much influence Trump still holds as a potential kingmaker with Republican voters.

The Ohio Senate race is also essential for the Democratic Party’s hopes of recapturing the US Senate, where Republicans currently hold a slim majority, in November. Former US Senator Sherrod Brown, a Democrat, is seeking to return to the Senate after losing his seat to a Republican challenger in 2024.

Who are the candidates for governor?

Amy Acton, the former head of Ohio’s Department of Health, is running unopposed in the Democratic gubernatorial primary and will face the Republican primary winner in November.

The Republican primary is more contested. While Ramaswamy has emerged as the party’s frontrunner, he faces a challenge from the populist right by Putsch, an auto racing engineer and right-wing political commentator.

Putsch, who the Associated Press reported had less than $9,000 in his campaign account at the end of April compared with $31m for his rival, has pitched himself as a more earnest representative of Trump’s “America First” ideology than Ramaswamy.

Ramaswamy has the endorsement of the state Republican Party as well as Trump himself, who called him “young, strong, and smart” while offering his “complete and total endorsement” in a social media post in November.

A third Republican candidate, Heather Hill, was disqualified after her running mate for lieutenant governor withdrew from the race, after the two spent several days exchanging insults over social media. Her name will still appear on the ballot, but her votes will not be counted.

Who is running for the US Senate?

The US Senate race in Ohio is expected to be one of the closest of the midterms and an important step towards the Democratic Party’s goal of snatching the majority from Republicans.

The special election will fill a Senate seat vacated by Vice President JD Vance, who was elected as Trump’s running mate in 2024.

Jon Husted, who was appointed to fill the seat temporarily after Vance stepped down, is running as the incumbent, unchallenged Republican candidate.

Former Senator Sherrod Brown, who lost his 2024 re-election race to Republican challenger Bernie Moreno, is considered the frontrunner in the Democratic primary.

He is facing Ron Kincaid for the Democratic nomination, but maintains a strong fundraising and name recognition advantage. Polls anticipate a tight race between Brown, considered the presumptive Democratic nominee, and Husted in November.

Do people need an ID to vote?

Ohio requires voters to show a form of identification, including a state driver’s licence, state ID card, passport, or military ID card.

IDs must be current and include a photograph and the voter’s name as it appears on the poll list to be accepted.

Republican lawmakers have long called for more stringent voter identification requirements, which they say are essential to safeguarding election integrity.

There is no evidence of widespread voter fraud in the US, but President Trump and his allies have used false claims of rampant illegal voting to push for greater restrictions on access to voting, including through methods such as mail-in ballots.

Who can vote?

Any registered voter can participate in any party’s primary elections. The state does not register voters by party, but considers voters affiliated with the party if they participate in its primary.