The results allowed both parties to claim partial victory, but highlighted an extraordinary realignment of USA voters by race, sex and education.
Throughout the midterm elections, Republicans had been anxious that Democrats would take the House as a so-called "green wave" of money flowed to Democratic candidates in the final weeks before the midterms.
His opponents say taking control of the House and Senate is the only way to stop Trump's agenda on issues like immigration, nominating judges, and healthcare.
Trump bucked tradition as a candidate by not releasing his tax returns.
Republicans, meanwhile, retained control of the Senate after GOP candidates unseated incumbent Democrats in IN and North Dakota and won an open seat in Tennessee.
As for the Senate race, despite Trump's deeply polarizing effect on voters, the GOP harnessed his rock-solid popularity with hard-right voters in rural, deep-red states.
That will give him pause for thought, even if he was putting his best gloss on the setback, tweeting that the evening had been a "tremendous success".
Health care and immigration were high on voters' minds as they cast ballots, according to a wide-ranging survey of the American electorate conducted by AP.
"I am extremely happy with the economy", Gerlock said.
The election on Tuesday may resolve some issues.
Trump encouraged voters to view the first nationwide election of his presidency as a referendum on his leadership, pointing proudly to the surging economy at recent rallies.
He bet big on a xenophobic closing message, warning of an immigrant "invasion" that promised to spread violent crime and drugs across the nation.
Two cities will split Amazon HQ2
If it does turn out to be Crystal City and New York City, we hope Amazon has a plan for how to deal with all the traffic. The Wall Street Journal reports that Amazon will split its much-anticipated HQ2 between two yet-to-be-named cities.
Midterm elections are often the "lounge act" to the presidential contest, as she puts it, but the battle for the House quickly spun into the signature contest of 2018. Republican incumbent Andy Barr fended off a strong challenge from Democrat Amy McGrath, a Naval Academy graduate and the first female Marine to pilot an F/A-18 Hornet in combat, in Kentucky's 6th Congressional district.
But White House spokeswoman Sarah Huckabee Sanders minimized the magnitude of likely Democratic gains. Democratic Senate incumbents were up for re-election, for example, in North Dakota, Indiana, and Missouri - states Trump carried by nearly 25 percentage points on average two years ago.
But the first result of the USA midterm elections is in: The island of Guam has a new female governor, Democrat Lou Leon Guerrero. Bob Menendez won a third Senate term, despite a federal bribery indictment that prosecutors dropped this year after a mistrial. The Justice Department dropped the charges after his trial ended in an hung jury.
But there are other areas in which the Democratic majority in the House will reshape policy. In Virginia, Democrats Elaine Luria and Abigail Spanberger toppled Republican Reps. The Republican incumbent had been branded Barbara "Trumpstock" by Democrats in a race that pointed to Trump's unpopularity among college-educated women in the suburbs.
If all that makes the midterms a success for Democrats, it still wasn't the censure party officials had hoped for.
As the one of the most volatile midterm elections in USA history wound down, the Democrats pulled closer to the 218 seats needed for a majority.
It also will test Trump's ability to compromise, something he has shown little interest in over the last two years with Republicans controlling both chambers of Congress. Independent candidate Shiva Ayyadurai (Massachusetts) has lost to Elizabeth Warren.
"I think everyone was bracing for any possible, insane scenario to show itself tonight but it basically looks like the baseline consensus forecast was correct", said Michael Purves, head of equity derivatives strategy at Weeden & Co, New York. Democrats also reclaimed a handful of blue-collar districts carried by both former President Barack Obama and Trump.
Daudt told The Associated Press that Republicans will lose the majority after Democrats flipped more than a dozen suburban districts.
A Democratic majority would break the Republicans' eight-year hold on the House that began with the tea party revolt of 2010. Democrats picked up some victories as well, defeating Reps.
Record diversity on the ballot may have helped drive turnout.
Three states could elect their first African-American governors, while several others were running LGBT candidates and Muslims. Pelosi, the minority leader and former speaker, intends to again seek the speakership; if she is successful, the 78-year-old veteran pol will become Trump's principal foil and foe.