As Americans head to the polls on Tuesday, the tight White House race between President Barack Obama and Republican Mitt Romney has narrowed to a fight over less than 10 states.

Obama's strategy is to solidify his last line of defense in the industrial Midwest, and to try to pluck away several insurance states from Romney's target list elsewhere.

Either he is wearing the best poker face in politics, or Mitt Romney is his own truest believer, so sure of his destiny as the next U.S. president that he refuses to contemplate the alternative.

"Confidence" is the singular word that senior strategist Stuart Stevens used to describe the Republican nominee's mood going into Tuesday's election, despite polls showing a slight lead for President Barack Obama.

Residents of the tiny northeastern town of Dixville Notch cast the first ballots of the White House race on Tuesday, with Barack Obama and Mitt Romney each receiving five votes.

The first-in-the-nation vote, held shortly after midnight, was tied for the first time in its history, another indication of the knife's edge separating the two candidates in a race that should be decided by the end of the day.

U.S. celebrities weighed in on the race for the White House on election eve Monday, endorsing their favorite candidates on Twitter or making last-ditch pleas for their followers to get out and vote.

Rapper Snoop Dogg endorsed the Democratic incumbent Barack Obama, tweeting: "Make sure u all vote 2morrow!! @BarackObama @MichelleObama."

Americans voted Tuesday in a nail-biting presidential election marked by the starkly different economic visions of Democratic incumbent Barack Obama and Republican challenger Mitt Romney.

The time for obsessing over key state opinion polls was over as the greatest political show entered its thrilling finale after an 18-month roller-coaster ride that exposed the nation's bitter polarization.

Barack Obama and Mitt Romney made their final cases to Americans on election eve Monday, capping a grueling, negative, multi-billion dollar campaign and handing their fates to voters.

"It all comes down to you, it is out of my hands now, it is in yours," a hoarse, moist-eyed Obama told a 20,000-strong crowd in Iowa, concluding his re-election bid in the state that nurtured his White House dream from 2007.

After a grueling 18-month battle, the final U.S. campaign day arrived Monday for President Barack Obama and rival Mitt Romney, two men on a collision course for the world's top job.

The candidates have attended hundreds of rallies, fundraisers and town halls, spent literally billions on attack ads, ground games, and get out the vote efforts, and squared off in three intense debates.

Just 48 hours before Election Day, the presidential race for the White House is tied, with both President Barack Obama and his Republican challenger, Mitt Romney, receiving 48-percent support among likely votes, a new poll has found.

The latest ABC News/Washington Post survey also showed Sunday that even independents, whose decision can push one of the candidates over the top, are now evenly divided: 46 percent favor Obama and 46 percent Romney.

U.S. President Barack Obama is keeping in constant touch with the huge emergency effort launched after superstorm Sandy, despite his intense final weekend on the campaign trail, aides said Saturday.

Obama started his day at the headquarters of the Federal Emergency Management Agency (FEMA) in Washington before heading to his first event in the swing state of Ohio.

President Barack Obama and Republican foe Mitt Romney Saturday power into a final weekend of campaigning before handing their fates to voters after a bitter, grueling White House race.

The rivals will chase one another through the battleground states that will decide Tuesday's election, with Obama seeking to solidify his midwestern line of defense, while Romney seeks an eleventh hour breakthrough.