Midterm Elections 2018 Results: When Will Results Come in and Reveal Who Won the House and Senate?

When the polls close across the country on Tuesday evening, the wait begins to see whether Democrats or Republicans come out on top in each race, and the bigger picture of which party will control the House of Representatives and the Senate.

Once the voting deadline rolls around, ballots will be counted at each polling station, but it will take a while for the results to come in. Polls in most states opened at 6 a.m. or 7 a.m. and generally will close between 7 p.m. and 9 p.m. local time. Specific times for each state are included on their websites. Time zone differences must also be factored in, with Hawaii and Alaska polling places closing at 11 p.m. and midnight ET, respectively.

Key districts might be able to call their races later in the night, meaning Americans may have a hint of who will control the House by midnight. The Senate was called for Republicans at 11:25 p.m. in the 2014 midterms by Associated Press.

But the larger states, and those with high turnout and a greater number of absentee ballots, are expected to take longer to count and may not have results out until the early hours of Wednesday at the earliest. For example, in 2014, California, the nation's most populous state, did not announce the victors of two House races until two weeks after the election.

House control may be known by 11 p.m. EST, when polls close in California, but there are more than a half-dozen close races in the state and many residents vote by mail. Expected high voter turnout this time around may also push the time of the results back deep into the night.

Meanwhile, some states require that a candidate win more than 50 percent of the vote to be declared the victor, or the top two candidates go into a runoff election. Notably, this could come into play in the closely fought battle for Georgia governor between Democrat Stacey Abrams and Republican Ron DeSantis.

midterm elections results when will we know who won
People cast their ballots at a community center during early voting, two weeks ahead of the key midterm polls, in Potomac, Maryland, on October 25. Results for the midterms will likely not be known until early the day after the elections. BRENDAN SMIALOWSKI/AFP/Getty Images

All 435 seats of the House, and 35 of the 100 Senate seats, are up for grabs.

Democrats must flip at least 23 GOP-held seats in order to regain the House. The Senate currently has 51 Republicans and 49 Democrats, meaning liberals would need to gain two seats to win control.

Polls show that Democrats are favored to win the House, while Republicans will likely keep their slim majority in the Senate.

The midterms are widely seen as a referendum on the president's performance. President Donald Trump hit the campaign trail heavy in recent weeks in support of Republican candidates and in a rally in Ohio Monday tied the midterm's outcome to the future of his legislative agenda and fending off calls for impeachment.

"In a sense, I am on the ticket," Trump said. "You've got to go out and vote."