Presidential elections aren't the only big elections in the United States.

Two years after a presidential election, U.S. citizens get to vote in midterm elections.

The President may not be on the ballot, but depending on schedules and term limits, a bunch of other candidates campaign for the vote.

On Nov. 6, the U.S. held another midterm elections.

What's at stake during midterm elections?

U.S. citizens will vote in candidates for the House of Representatives (all 435 seats) and the Senate (35 of 100 seats), which together make up Congress.

Before the midterm elections, Republicans held majority seats in both the House of Representatives and the Senate.

Governors of U.S. states may also seek election during the midterms.

And from time to time, other initiatives make their way to the ballot in a kind of referendum.

So even in a non-Presidential year, Americans still have a lot to vote for. But how did things go down in the Congress elections of 2018?

The House

The U.S. Congress is split into two chambers. The House is the lower chamber of Congress, responsible for proposing new legislation.

A House Representative is kind of like an MP, representing your particular district in the nation's capital.

Going into the 2018 election, the Republicans held a commanding lead of 235 representative seats to the Democrats' 193, with seven vacancies.

The Democrats had an uphill task of winning a majority 218 seats when it came to the House of Representatives, which has 435 members.

Each Representative's term lasts two years, which mean they must seek re-election every two years.

What happened?

As of 7:00 pm on Nov. 7 (Singapore time), the Democrats have officially retaken the House.

At least 218 Democrat candidates have confirmed their victories.

There are still many races left to be called, particularly in Western states like California and Alaska. But the Democrats have reached the magic number of 218.

A number of milestones were also reached, including the first two Muslim women and the first two Native American women elected to Congress.

A record number of women is expected to serve in the next Congress, from both parties.

Democrats have seized control of the U.S. House, giving them power to investigate President Trump and block much of his agenda. Find AP’s full coverage on our midterm elections site. #Election2018 https://t.co/tnNrlrq2Lt

— The Associated Press (@AP) November 7, 2018

What's next?

With the control of the House passing over to Democrats, Rep. Nancy Pelosi of California is expected to make another bid to become Speaker of the House.

The Speaker is a powerful position, usually responsible for shaping a party's legislative effort.

Democrats will also control a number of influential House Committees, which provide oversight in fields like Intelligence, Armed Services, and the Judiciary.

Some Democrats have signalled that they will waste little time in launching investigations into various practices of the Trump Administration.

For example, Rep. Maxine Waters of California is likely to assume the Chair of the House Financial Services Committee, and may subpoena President Trump's tax returns.

It is true that this #midtermelection today is the most important election of our lifetime. The phenomenal early voting numbers are because of young, first time voters. Millennials are going to move our country forward.

— Maxine Waters (@RepMaxineWaters) November 6, 2018

The Senate

The Senate is the upper chamber of Congress, who review and approve legislation. They are also responsible for judiciary appointments, among other duties.

Each US state elects two Senators for a total of 100 Senators. If there is a tie in the Senate, the Vice-President has the power to cast a tie-breaking vote.

Senators serve six-year terms.

For 2018, 35 senate seats were up for elections -- the remaining 65 senate seats have not completed their current terms.

Going into the elections, the Republicans counted 51 Senators among their ranks.

The Democrats had 47. There are also two Independent Senators, Angus King of Maine and Bernie Sanders of Vermont, who usually vote along the same lines as the Democrats.

What happened?

The relatively quick defeat of Democrat Sen. Joe Donnelly in Indiana to Republican challenger Mike Braun was a sign of things to come.

Another nationally popular Democratic candidate, Beto O'Rourke, failed to unseat Republican incumbent Ted Cruz in Texas.

As of 7:00 pm on Nov. 7 (Singapore time), the Republicans have confirmed at least 51 Senate seats.

This included impressive projected victories in the populous and hard-fought states of Texas, Florida (Rick Scott) and Missouri (Jay Hawley).

They look set to pick up even more seats in the Senate once the final results are in, and with the states of Arizona and Montana still up in the air.

The only bright spots for the Democrats were in Nevada, where challenger Jacky Rosen is projected to beat incumbent Republican Dean Heller, and West Virginia, where incumbent Joe Manchin hung on to his seat.

Thank you, Texas! Now let's get back to work to defend jobs, freedom, and security for Texas and America! #TXSen pic.twitter.com/1XGbQt91a7

— Ted Cruz (@tedcruz) November 7, 2018

What's next?

The U.S. Senate is responsible for confirming Presidential appointments, like his Cabinet members, Ambassadors and nominees to the Supreme Court.

You may remember the contentious nominee of Brett Kavanaugh to the Supreme Court in Oct. 2018, which passed by 50 to 48 votes.

If another member of the Supreme Court dies or resigns, President Trump will find it an easier task for his next nominee.

Meanwhile, Senate Majority Leader Mitch McConnell of Kentucky will push forward with his agenda of confirming federal judges and reviewing trade deals.

2020

The dust may just have settled in 2018.

But already, political observers are looking forward to 2020 -- and the next U.S. Presidential election.

President Donald Trump sent an upbeat tweet about the night's result:

Tremendous success tonight. Thank you to all!

— Donald J. Trump (@realDonaldTrump) November 7, 2018

But with the end of one-party rule in the United States, things may get more contentious for him and the Republicans in the years ahead.

Top image from President Donald Trump's Facebook page.