One of the most divisive and bitterly fought elections in modern American history has neared its climax as the candidates delivered the final speeches of their campaigns.
Tens of millions of voters across the United States will now decide on the next occupant of the White House as polling stations open across the country.
Hillary Clinton aims to become the first female president in US history, while tycoon Donald Trump hopes his pledge to "Make America Great Again" will win over voters in key swing states.
Democratic hopeful Clinton has a narrow lead in the opinion polls and at a last rally in Raleigh, North Carolina, she urged voters to reject Trump's "dark and divisive" vision.
The last push came after a star-studded event in Philadelphia earlier on Monday evening that saw speeches from President Barack Obama, first lady Michelle Obama and former president Bill Clinton.
Obama thanked Americans for choosing "a skinny guy with a funny name".
Clinton's campaign suffered a setback in the closing stages with the FBI examining a fresh cache of emails linked to the private server she used as secretary of state, with the announcement that she was in the clear only coming on Sunday.
Victory for Clinton would see her follow husband Bill into the White House, with the former president becoming the first gentleman - or "first laddie", as some have suggested.
Republican rival Trump, who has been dogged by allegations of misogyny and sexual misconduct, continued his tour of the country on Monday, targeting battleground states in an effort to get the 270 electoral college votes he needs to become one of the most unlikely victors of a presidential race.
In the early hours of Tuesday at a final rally in Grand Rapids, Michigan, he declared: "Today is our Independence Day. Today the American working class is going to strike back."
The businessman and TV personality, who has courted controversy at every stage of his campaign, had to fight against the Republican hierarchy to become the nominee and enjoys an uneasy relationship with the Grand Old Party.
But the maverick, anti-establishment message from a man who has never held public office has struck a chord with blue-collar Americans.
The frenetic pace of his campaign showed no sign of letting up, with addresses at rallies in the key states he needs to win to enter the White House.
"You have one magnificent chance to beat the corrupt system and deliver justice," Trump told a rally in Florida. "Do not let this opportunity slip away."
Both candidates will be in New York on election night, with the Republican billing his planned event at a Hilton hotel as a "victory party".
Security is expected to be tight as Americans go to the polls after US authorities received intelligence of a possible pre-election al Qaida attack, and more than 5,000 police officers will be assigned to secure central Manhattan.
Barack Obama will remain in the White House until January 20 when the election winner will take the oath of office and become the 45th president of the United States.
Other candidates running for the presidency include Gary Johnson of the Libertarian Party, the Green Party's Jill Stein and conservative independent Evan McMullin.