But network projections said that Democrats would take control of the House for the first time in eight years, upending the balance of power in Washington where Trump enjoyed an easy ride following his shock 2016 election with Republican dominance of both chambers. The House was also getting its first two Muslim women, MA elected its first black congresswoman, and Tennessee got its first female senator.
They also could force Trump to scale back his legislative ambitions, possibly dooming his promises to fund a border wall with Mexico, pass a second major tax-cut package or carry out his hardline policies on trade.
A simple House majority would be enough to impeach Trump if evidence surfaces he obstructed justice or that his 2016 campaign colluded with Russian Federation.
Trump sought to take credit for retaining the GOP's Senate majority, even as the party lost control of the House.
Faced with the possibility of keeping the Senate but losing the House, aides in recent days had laid out the political reality to Trump, who could face an onslaught of Democratic-run investigations. Moscow denies meddling and Trump denies any collusion.
"We will have a responsibility to find our common ground where we can, stand our ground where we can't", Pelosi said. Democrats flipped seats in suburban districts outside of Washington, Philadelphia, Miami, Chicago and Denver.
Democrats were most optimistic about the House, a sprawling battlefield set largely in America's suburbs where more educated and affluent voters in both parties have soured on Trump's turbulent presidency, despite the strength of the national economy.
All 435 seats in the House, 35 seats in the 100-member Senate and 36 of the 50 state governorships were up for grabs.
Yet Democrats' dreams of the Senate majority as part of a "blue wave" were shattered after losses in Indiana, Tennessee, North Dakota and Texas.
Though liberal voters across the country are fired up after the first two years of Republican control, it's far from guaranteed that they'll turn up in great enough numbers to deliver the House and Senate back to Democrats.
Some of the biggest Democratic stars of the campaign season were struggling, with Beto O'Rourke's underdog US Senate campaign to oust Ted Cruz in conservative Texas failing. While, Colorado Democrat Jared Polis has been elected as the first openly gay US Governor while, Kansas Democrat Sharice Davids became first Native American woman in Congress.
It would also once again push up the turnover figures for Mr Trump's White House, already one of the highest for a modern-day president.
GOP hopes of gaining a seat from New Jersey were dashed when Democrat Sen.
After a special state Senate election in 2017, Democrats gained control of that chamber by one vote, giving them unified control in Olympia this year.
GOP Whip Steve Scalise of Louisiana predicted his party would retain a slim majority, saying on election eve: "In the end, we hold the House because of the strong economy".
In Arizona, where Democrat Kyrsten Sinema and Republican Martha McSally are locked in a dead heat, Trump's approval is 52%, with 47% who disapprove.
In total, Trump had held 26 rallies since October, embracing Democrats' attempts to make the election a referendum on his agenda.
On Tuesday, that pitch was tested, and the results were a split decision: Trump helped lead his party to gains in the Senate but a significant loss of seats in the House.
US President Donald Trump. Perhaps more important, they would claim subpoena power to investigate Trump's personal and professional shortcomings.
Although moderate Republicans who remain in the House may view the result as an indictment of Donald Trump's strategy of focusing relentlessly on illegal immigration in the final stretch of the campaign, they will be a small minority.