By late evening, they had captured 50 seats held by Democrats and led in another 19 districts. Democrats had only picked up 2 Republican seats, and had lost some of their most powerful members, including Rep. John Spratt in South Carolina, the 14-termer who heads the Budget Committee, and Rep. Ike Skelton in Missouri, the Armed Services Committee chairman.
Republicans were on track to their biggest House gains since they picked up 80 seats in 1938.
The GOP needed a net gain of 40 seats to win back control of the House that they lost in 2006.
Overall, Republicans had won 206 seats and led for 36 others. Democrats had won 143 and lead for 44.
Republicans quickly pledged to heed the message of angry voters who they acknowledged were rejecting what both parties had to offer.
"Across the country right now, we are witnessing a repudiation of Washington, a repudiation of big government, and a repudiation of politicians who refuse to listen to the people," said Rep. John Boehner of Ohio, in line to become speaker in a new Republican-led House.
Republicans defeated more than two dozen Democrats in districts won by Sen. John McCain of Arizona in the 2008 presidential campaign, as voters expressed disillusion with President Barack Obama, anxiety about the economy and tea party-fueled distaste for government. GOP gains were particularly pronounced in the Rust Belt, with the party racking up two wins in Indiana, five each in Ohio and Pennsylvania, three in Illinois, and two in Michigan. They'd scored key victories from Maryland to Colorado and broken House Democrats' monopoly in New England by defeating Rep. Carol Shea Porter in New Hampshire.
Among the victims were Ohio Rep. Steve Driehaus, Florida Reps. Suzanne Kosmas, Frank Kratovil of Maryland and Tom Perriello of Virginia, first-termers who backed key elements of Obama's agenda - the president even campaigned for Perriello - and were savaged for it by their Republican rivals.
But those who stressed their independence from their party, like Reps. Glenn Nye of Virginia and Travis Childers of Mississippi also went down. Some old bulls also fell, including nine-term Rep. Earl Pomeroy in North Dakota, 13-term Rep. Paul Kanjorski in Pennsylvania and 20-year veteran Rep. Chet Edwards in Texas.
Democrats had few victories to celebrate. In one rare bright spot, John Carney handily beat Republican Glen Urquhart in the race to succeed GOP Rep. Mike Castle in Delaware's only House seat, which Castle left to unsuccessfully pursue a Senate seat. And in New Orleans, Democrat Cedric Richmond beat Rep. Anh "Joseph" Cao, who had campaigned as a friend of Obama.
A handful of Democrats heavily targeted by the GOP pulled through, including Reps. Betty Sutton of Ohio, Joe Donnelly of Indiana, Heath Shuler of North Carolina and John Yarmuth of Kentucky.
"Democratic turnout has been higher than projected," said Rep. Chris Van Hollen of Maryland, the Democratic campaign chief. "We knew it would be challenging, but also knew people understood how high the stakes were in this election.
But those successes were eclipsed by the scope of potential Democratic defeats. First-termers were lagging in key races and some of the party's old bulls were struggling to survive, like Rep. Ike Skelton in Missouri.
Democrats now control the House by a 255-178 margin, with two vacancies. All 435 seats are up for grabs.
Voters went to the polls intensely worried about the economy and dissatisfied with the way the federal government is working. An Associated Press analysis of exit poll results found voters saying the economy eclipses any other issue as their top concern. They're also expressing dissatisfaction with Obama and Congress, and they don't have a favorable view of either political party.
It was a remarkable turnabout from 2008, when Obama helped propel Democrats to big gains in their House majority only two years after the 2006 wave that swept them to control. This year, few Democratic incumbents felt safe, least of all the 51 who claimed Republican seats over the last four years.
House candidates and party committees raised and spent tons of campaign cash, and Democrats had a slight edge. The Democratic Congressional Campaign Committee spent $145 million to bankroll its candidates, compared with $121 million shelled out by the National Republican Congressional Committee. That's nearly double what the Democratic campaign arm spent in the last election, and more than five times what the Republican counterpart did when the tables were turned.
GOP candidates poured a total of $419 million into their campaigns, while Democrats spent $421.5 million.
But Republican-allied outside groups skewed the playing field dramatically. They spent $189.5 million savaging Democratic candidates while independent groups skewering Republicans spent $89 million.