The crucial midterms will determine how much power President Donald Trump has to make changes in the last two years of his term.

The first polling stations opened at 5 a.m. (1000 GMT) in the eastern US state of Vermont for the midterm elections.

Voting is to follow in Connecticut, Indiana, Kentucky, Louisiana, Maine, Missouri, New Jersey, New York and Virginia from 6 a.m. local time. And polls open in West Virginia, North Carolina and Ohio at 6:30 a.m.

More than 57 million ballots were cast early in 47 states and Washington DC as of Monday. Many more votes will be cast in person on Tuesday.

Polling stations across the country close between 6 p.m. and 9 p.m., with vote counting beginning immediately afterwards.

Why the midterms matter and which races to watch
US citizens are voting in Tuesday's midterms for who they want to see in the Capitol.

Midterm elections are held every four years, at the exact halfway point between presidential elections.

The people of the United States decide who will represent them in the two chambers of the US Congress, the House of Representatives and the Senate. Some states are also voting for their governor.

These are the decisions on the ballot paper — but they are not the only thing voters will be taking into account.

J. Miles Coleman, an election analyst at the Center for Politics at the University of Virginia, explained before the last midterms that they were "often a referendum on the president and party currently in power."

If the people are content, the party of the leader in the White House does better than if the people are predominantly dissatisfied. President Donald Trump's approval ratings are currently at a record low.

When can we expect results?
The first results will likely start arriving on Tuesday evening after polls begin to close, but it could take hours or even days for the outcome of some closely contested races to become clear.

The first polling stations close in Indiana and Kentucky at 6 p.m. local time (2300 GMT), followed by Georgia, South Carolina, Vermont and Virginia one hour later.

Votes cast on election day are often processed before mail-in ballots, which means the overall result can shift significantly as the count progresses.

Results will come in throughout Tuesday evening and Wednesday morning as states release their vote counts.

US media outlets may start to make calls and projections based on exit polls and early counts from state election officials.

Several outlets, including DW, rely on the Associated Press for race calls.

In 2022, the Senate results weren't finalized until four days after the election, while for the House of Representatives results it took eight days. In the midterms before that, the outcome was already clear on election night.