The Senate is getting several new members as Republicans retain control. A look at some of the new senators, all but one a Republican from a state where US President Donald Trump remains popular:
Jacky Rosen (Nevada Democrat)
Nevada's newest senator, Jacky Rosen, decided to take on incumbent Republican Sen. Dean Heller last year when she was only six months into her first term as congresswoman from the Las Vegas area.
Rosen, 61, a former computer programmer and software consultant, narrowly won election two years ago to what had been a GOP-held US House seat. She was serving as president of a synagogue when longtime Nevada Sen. Harry Reid recruited her to run for office against incumbent Republican Rep. Joe Heck after several others declined to run.
Rosen hammered Heller throughout the campaign this year for his shifting stances on health care and his new alliance with US President Donald Trump. He was considered the most vulnerable GOP senator this year, and the only one seeking re-election in a state that Hillary Clinton carried in 2016.
Rosen, a Chicago native and University of Minnesota psychology graduate, moved to Las Vegas in 1980 and briefly worked as a waitress at Caesars Palace. Nevada will now be one of half a dozen states represented by US senators who are both women.
Josh Hawley (Missouri Republican)
Democrat Claire McCaskill's good fortune finally ran out on Tuesday when Republican Josh Hawley flipped a crucial Senate seat in Missouri.
Republicans in increasingly conservative Missouri felt they missed an opportunity in 2012 when Senate hopeful Todd Akin's candidacy imploded after he said victims of "legitimate rape" rarely get pregnant.
This year party leaders united behind the 38-year-old Hawley, who had been in office less than two years as attorney general. He relentlessly attacked McCaskill as too liberal for a state Trump won by 19 percentage points in 2016, criticising her for failing to vote for Supreme Court Justice Brett Kavanaugh.
Trump campaigned on Hawley's behalf several times including twice in the week before Election Day.
Hawley grew up in Lexington, Missouri, near Kansas City. He has a bachelor's degree from Stanford and a law degree from Yale. He served as a law clerk for US Chief Justice John Roberts and taught as an associate professor at the University of Missouri School of Law
Hawley's work history includes a stint with the Becket Fund for Religious Liberty in Washington, DC, where he was part of the legal team for Hobby Lobby in its successful lawsuit against a contraceptive mandate of the Affordable Care Act.
Mike Braun (Indiana Republican)
Indiana's next senator is a little-known Republican businessman previously elected to two sleepy terms in the state Legislature, where one of his most notable actions was a vote to increase taxes.
But what multimillionaire auto parts magnate Mike Braun may lack in name recognition, he more than made up for by lending more than $10m of his own fortune to his campaign.
That enabled him to beat two sitting congressmen, Luke Messer and Todd Rokita, in a bitter GOP primary, and then topple Democratic Sen. Joe Donnelly in Tuesday's general election.
Donnelly was one of the most vulnerable Democrats up for re-election in a state Trump carried two years ago.
Worth somewhere between $37m and $95m, Braun came to politics after building a business empire that includes a trucking company and a national auto parts distribution business, Meyer Distributing. It has more than 800 employees and 70 locations across the US.
Braun is a graduate of Wabash College and Harvard Business School, where he earned an MBA in 1978. He married his wife, Maureen, in 1976. They have four children.
Before launching his political career as a Republican, Braun voted in Democratic primaries until shortly before he first ran for the statehouse in 2014. He previously served as a member of a local school board.
Kevin Cramer (North Dakota Republican)
Kevin Cramer's admirers call it reckless honesty - an unfiltered way of thinking and talking that can be refreshing while sometimes getting him in trouble.
It was on display late in his Senate campaign when he minimised Christine Blasey Ford's allegation of sexual assault by Supreme Court nominee Brett Kavanaugh by characterising them as "teenagers who evidently were drunk". As with some other statements during his career, Cramer found himself explaining and defending the remark - but eventually riding out the damage.
The 57-year-old Cramer's free-speaking style comes with remarkable accessibility, too. He employs his wife, Kris, as his campaign manager but most often fields questions himself, routinely sharing his cell number with reporters and rarely turning down an interview.
The former chairman of the state Republican Party has done a little bit of everything in his long career: State tourism director, state economic development director, Public Service Commission member. On the powerful PSC, Cramer regulated everything from oil pipelines and utilities to auctioneers, and left no doubt about his strong pro-oil and pro-coal outlook.
Cramer ran three times for the US House before finally breaking through in 2012.
Marsha Blackburn (Tennessee Republican)
Tennessee is replacing Bob Corker, one of the Senate GOP's most outspoken critics of Trump - at least at times - with a close ally of the president in Marsha Blackburn.
Blackburn is a firm backer of Trump's US-Mexico border wall, has sung the praises of his tax cuts, and came out in support of Brett Kavanaugh's confirmation to the Supreme Court the day Trump nominated him.
Blackburn, who was first elected to the House in 2002, has aligned with the tea party movement and regularly appeared on Fox News. She opened her campaign by dubbing herself a "hardcore, card-carrying Tennessee conservative".
Before that, she made a name for herself as a state senator who helped lead the revolt against a failed Tennessee income tax proposal in the early 2000s. She also served as executive director of the state's Film, Entertainment, and Music Commission.
The 66-year-old from the Brentwood suburb of Nashville attended college on 4-H scholarship and worked her way through school selling books as the first woman ever hired by her company. She then worked for a regional department store chain as director of retail fashion and special events, and later founded a marketing company focused on retail.