The icing on the cake is that the Democrats may still win a majority in the US Senate, if two tough contests in Montana and Virginia go the party's way. The Montana and Virginia Senate races are so close that a recount may decide the eventual result.
Reports say the Democrats have won 234 seats in the 435-member House of Representatives against the Republicans' 201 seats.
A Democratic win paves the way for the United States' first lady Speaker in Nancy Pelosi. The Speaker is the head of the US House of Representatives.
Tuesday night's win gives the Democrats control of the House for the first time since the Newt Gingrich-helmed Republican revolution of 1994.
In the 100-member Senate, the Democrats went into the November election needing six seats to regain control and have thus far picked up three.
Though it won't count in their official tally, the Democrats also have a disguised win in incumbent Senator Joe Lieberman, who defeated Democratic candidate Ted Lamont in Connecticut.
Lamont, campaigning on the theme that Lieberman was too close to President George W Bush for comfort, had knocked out Lieberman in the Democratic primaries earlier this year.
The veteran Senator, who fought as an Independent and has won the race, has vowed that he will vote with the Democrats on most issues. His win, thus, effectively gives the Democrats a fourth seat.
The Democrats are also within sight of controlling a majority of state governorships, again for the first time in 12 years.
Going into the November polls, the party needed to win four governorships, in 36 races, to reach the magic number of 26 in America's 50 states -- and already, the party is projected to win at least five Republican-held governorships, while holding on to their own.
The Democratic surge in the House of Representatives has depended on holding on to most of their own seats while making major inroads into Republican holdings. Key races, from this perspective, include Ohio's 18th Congressional District, where Democrat Zack Space defeated Republican Joy Padgett.
The seat was formerly held by Republican Bob Ney, who resigned last Friday after pleading guilty to corruption charges stemming from the influence-peddling scandal revolving around super-lobbyist Jack Abramoff.
Democrat Tim Mahoney is poised to defeat Republican Joe Negron in Florida's 16th District. The seat opened up following the resignation of Republican Mark Foley, following revelations that he had sent lurid e-mails to under age Congressional pages.
In the current House, Republicans hold 230 seats against 201 to the Democrats, and 1 Independent.
In the Senate, where Republicans currently hold 55 seats against 44 by the Democrats, the latter came into the race needing to pick up six seats out of 33 to wrest control.
Of the 33 seats up for grabs, 17 are Democratic, and 15 are held by Republicans.
Thus far, the Democrats look like holding on to their own seats, while making major gains in Republican strongholds.
The biggest upset on the Senate side is the defeat of Rick Santorum, the third-ranking Republican in the Senate, in Pennsylvania at the hands of Democratic candidate and former state
Also topping the list of upsets is Republican Mike DeWine in Ohio who lost badly to Democratic challenger Sherrod Brown, a US Congressman and member of the Congressional Caucus on India and Indian Americans.
The anti-Republican sentiment is hurting even liberal Republicans, as in Rhode Island where Lincoln Chaffee, who has voted against his party on some key issues including stem cell research, headed for an upset defeat at the hands of Democratic challenger and former attorney general Sheldon Whitehouse.
On the governorships side, with 36 states in play, the Democrats are currently ahead in Massachusetts, where Deval Patrick, a former member of the Clinton administration, is poised to become the state's first black governor.
Democrats are also winning in New York, where Attorney General Elliot Spitzer will succeed incumbent George E Pataki; in Ohio, where Congressman Ted Strickland, making a play for the state chair, is set to defeat Ken Blackwell; and in Maryland, where Martin O'Malley is poised to defeat incumbent Robert Ehrlich.
In Arkansas, where incumbent Mike Huckabee has reached his term-limit, Democrat Mike Beebe is poised to defeat Republican Asa Hutchinson, formerly an undersecretary in the Department of Homeland Security.
Democratic governors will likely hold on to their seats in Kansas, Oklahoma, Arizona, Illinois, Michigan, Oklahoma, New Mexico, Pennsylvania, Wyoming, South Dakota and Tennessee. Republicans look set to retain Nebraska, Connecticut, Georgia, South Carolina and Texas.
Exit polls meanwhile show a curious phenomenon: though pre-poll punditry suggested that the war in Iraq would likely be the key issue, voters indicate that corruption -- and ethics in government -- was top of the mind as they prepared to cast their ballots.
More than a defeat in the polls, this could in fact be the crushing blow to Republican morale -- the party had swept to power in Congress in 1994 on the pledge of restoring morality to the government; that, too, was the prime theme of George W Bush's presidential campaign of 2000.
The time-honored Republican strategy of tacking on red-meat issues to energise the faithful and get them to vote -- reportedly a brainchild of its ace strategist Karl Rove, and used to very good effect in the President George W Bush re-election campaign of 2004 -- also appears to have failed the party this time.
In the heavily Republican state of Arizona, thus, Proposition 107, that seeks to ban same sex marriage, is headed for defeat. Proposition 85 in California, helmed by Republican Governor Arnold Schwarzenegger, that seeks to deny abortion to girls under the age of 18 without parental notification, is also poised to be voted down; a similar measure proposed in Oregon is also headed for defeat.
Colorado has the most number of such issues on the ballot -- and these seem to be going the Republican way. A referendum on Domestic Partnerships, that seeks to give same sex couples the same legal protections as those enjoyed by man-woman pairings, is getting the thumbs down. Amendment 43, which seeks to ban same sex marriage, is headed for a win (Idaho, Virginia, Wisconsin and South Carolina are also poised to ban same sex marriage). Another amendment, that seeks to legalise marijuana, has been heavily opposed and is likely to be voted out, judging by early trends.