"It's the night we have been waiting for," said House Speaker Nancy Pelosi, D-Calif.
Ousting 22-year veteran Rep. Chris Shays in Connecticut gave Democrats every House seat from New England. Their victory in an open seat on New York's Staten Island gave them control of all of New York City's delegation in Washington for the first time in 35 years.
Democrats also rode the coattails of a decisive victory by Barack Obama in New Mexico to win one House seat they haven't controlled in four decades and another the GOP had held for 28 years. Both were left up-for-grabs by GOP retirements.
Democrats unseated a half-dozen Republican incumbents and captured eight open GOP seats, capitalizing on the unusually high 29 Republican departures. Republicans knocked off three Democratic incumbents.
With more than 380 of the 435 House races decided, Democrats held leads for a dozen other Republican-held seats. Republicans were leading in fewer than a handful of seats held by Democrats.
For the first time in more than 75 years, Democrats were headed for big House gains in back-to-back elections. The picked up 30 seats in 2006.
"This will be a wave upon a wave," Pelosi said.
In the first sign of what promises to be a bitter round of GOP recriminations, Rep. Adam Putnam of Florida, the No. 3 Republican, told colleagues in a letter released near midnight that he was "reluctantly" stepping down from his post.
In the northeast, GOP Reps. John R. "Randy" Kuhl of New York and Phil English of Pennsylvania were defeated. Democrat Eric Massa unseated Kuhl in New York's southern tier, and Kathy Dahlkemper, a 50-year-old mother of five, toppled English in a swing district of rural communities and old industrial steel towns in Pennsylvania's northwest corner.
In Connecticut, Democrat Jim Himes, a Greenwich businessman, defeated Shays despite the Republican's highly publicized late criticism of McCain's presidential campaign.
In upstate New York, former congressional staffer Dan Maffei won election to succeed retiring GOP Rep. Jim Walsh, becoming first Democrat in nearly 30 years to represent the district around Syracuse. Downstate, Democratic city councilman Mike McMahon won the race on Staten Island to succeed GOP Rep. Vito Fossella, R-N.Y., who was forced to resign amid drunk driving charges and revelations that he fathered a child from an extramarital affair.
New Jersey Democratic state Sen. John Adler won election to succeed retiring Rep. Jim Saxton, R-N.J., in the state's Pine Barrens region.
In the South, too, Democrats made inroads. High school civics teacher Larry Kissell won election in North Carolina, defeating Republican Rep. Robin Hayes. Democrat Gerald Connolly, a former chairman of the Fairfax County Board of Supervisors, was elected to succeed retiring GOP Rep. Thomas M. Davis III in a northern Virginia district that's trending more Democratic because of an influx of new voters. And in a far more conservative district further south, Rep. Virgil H. Goode Jr.,R-Va., was in a too-cloe-to-call race for survival against Democrat Tom Perriello.
In Florida, GOP Rep. Tom Feeney - under fire for ties to disgraced lobbyist Jack Abramoff - was the first incumbent to fall, losing to former state Rep. Suzanne Kosmas. To the east, Rep. Ric Keller, R-Fla., lost to Democratic attorney Alan Grayson, in an increasingly Hispanic district in Orlando.
Democrats also made inroads in the West, where they captured the two New Mexico seats and one left open by retiring GOP Rep. Rick Renzi, who's awaiting trial on corruption charges.
In Illinois, Democrat Debbie Halvorson, the speaker of the state Senate, won election to a seat held by retiring GOP Rep. Jerry Weller in the swing exurbs and rural areas south of Chicago.
The news wasn't all good for Democrats. Republican attorney Tom Rooney defeated first-term Democratic Rep. Tim Mahoney of Florida, who had admitted to two extramarital affairs just weeks before Election Day.
Republican Bill Cassidy dealt a bruising defeat to Rep. Don Cazayoux, D-La., elected in a special election six months ago.
And in Texas, Republican Pete Olson, a former chief of staff to Sen. John Cornyn, beat Democratic Rep. Nick Lampson.
But other freshman Democrats once considered vulnerable cruised to easy re-election.
First-term Democratic Reps. John Yarmuth of Kentucky, Indiana's Joe Donnelly and Brad Ellsworth, and New Hampshire's Rep. Carol Shea-Porter won easy re-election. They were part of a crop of freshman Democrats in conservative-leaning districts who began compiling campaign war chests and moderate voting records almost from the moment they were elected two years ago, leaving only a few of them endangered on Tuesday.
Former five-term Republican Rep. Anne Northup was unable to mount a comeback in Louisville, Ky., against Yarmuth despite GOP presidential nominee John McCain's decisive victory in the state.
In 2006, Democrats won 30 seats and control of Congress in a surge powered by voter anger over the Iraq war.
This year the sour economy and public antipathy for President Bush posed the biggest challenges for Republican candidates. The Democrats were aided by a wave of GOP retirements and huge financial and organizational advantages over Republicans.
That's despite voter hostility toward the Democratic-controlled Congress. Just one in five voters Tuesday approved of the job Congress was doing, about as poorly as Bush fared, according to AP exit polling.
Six in 10 voters cited the economy as the most important issue facing the nation. About half said the economy is poor and nearly all the rest said it's not good. The results were based on a preliminary partial sample of nearly 10,000 voters in Election Day polls and in telephone interviews over the past week for early voters.
Democrats now control the House by a 235-199 margin, with one vacancy.
GOP lawmakers at risk included Alaska's Rep. Don Young, Colorado's Rep. Marilyn Musgrave, and Michigan's Reps. Tim Walberg and Joe Knollenberg. Rep. Lee Terry of Nebraska, once considered a safe bet for re-election, was also in major trouble.
Rep. John P. Murtha, D-Pa., who chairs a subcommittee with the most influence on the Pentagon's spending, who had a scare after calling his district south of Pittsburgh "racist," won easy re-election.
Democratic candidates raised $436 million, compared with Republicans' $328 million, according to federal data compiled by the nonpartisan Center for Responsive Politics. The Democratic Congressional Campaign Committee poured $76 million into competitive races and the National Republican Congressional Committee spent $24 million.
Because hurricanes delayed October primaries, two Louisiana seats - one that belonged to retiring Republican Rep. Jim McCrery and another held by indicted Democratic Rep. William Jefferson - won't be decided until December. Those districts held primaries Tuesday.
(Copyright 2008 by The Associated Press. All Rights Reserved.)