Presidential hopefuls Hillary Clinton and Donald Trump blitzed through battleground states on Monday in a final bid to energise supporters as they raced towards the election finish line.
Mrs Clinton urged voters to embrace a "hopeful, inclusive, bighearted America," while Mr Trump called for support to "beat the corrupt system."
The candidates planned to campaign late into the night, a frenzied end to a bitter election year that has laid bare the nation's deep economic and cultural divides.
Mrs Clinton opened the day buoyed by FBI Director James Comey's announcement on Sunday that he would not recommend criminal charges against her following a new email review.
The inquiry had sapped a surging Clinton momentum at a crucial moment in the race, though she still heads into election day with multiple paths to the 270 Electoral College votes needed to become the nation's first female president.
"I think I have some work to do to bring the country together," she acknowledged as she boarded her plane for her last battleground tour. "I really do want to be the president for everybody."
As she took the stage in Pittsburgh, supporters yelled out, "We love you" - an unusual occurrence for the Democratic presidential candidate who has sometimes struggled to connect with voters.
"I love you all, too. Absolutely," Mrs Clinton said with a chuckle.
Mr Trump was aggressive to the end, repeatedly attacking his rival at his first event of the day in Sarasota, Florida. Having made the new FBI review a centerpiece of his closing case to voters, he argued that Mrs Clinton was being protected by a "totally rigged system".
"You have one magnificent chance to beat the corrupt system and deliver justice," Mr Trump said. "Do not let this opportunity slip away."
At his second stop of the day in battleground North Carolina, he told a Raleigh audience: "You've got a half a day to make every dream you've ever dreamed for your country and for your family to come true."
He has been predicting victory, but said if he doesn't win, he'll consider it "the single greatest waste of time, energy and money".
Across the country, nearly 24 million early ballots were cast under the shadow of Mr Comey's initial announcement of a new email review. That number represents more than half of the roughly 42.5 million people who had cast votes by Monday afternoon, according to Associated Press data.
The inquiry involved material found on a computer belonging to Anthony Weiner, the disgraced former congressman and estranged husband of Huma Abedin, a long-time Clinton aide. Mr Comey said on Sunday the FBI reviewed communications "to or from Hillary Clinton while she was secretary of state".
Mrs Clinton tried to fly above the controversy on Monday and was not expected to address the matter during stops in Michigan and North Carolina. She was also headlining an evening rally in Philadelphia with President Barack Obama and first lady Michelle Obama, along with rock stars Bruce Springsteen and Jon Bon Jovi.
Nearing the end of his two terms in the White House, Mr Obama was nostalgic as he launched his own busy day of events, noting that he was probably making his last campaign swing for the foreseeable future.
"Whatever credibility I have earned after eight years as president, I am asking you to trust me on this. I am voting for Hillary Clinton," Mr Obama said.
Mrs Clinton is banking in part on high turnout - particularly among Mr Obama's young, diverse coalition of voters - to carry her over the finish line on Tuesday. Roughly half the states with advance voting have reported record turnout, including Florida and Nevada, which have booming Hispanic populations, a possible good sign for her.
In Florida alone, Hispanic participation is up by more than 453,000 votes, nearly doubling the 2012 level. Black turnout is up compared to 2012, but that share of the total vote is lower due to bigger jumps among Latinos and whites, according to University of Florida professor Daniel Smith
In Nevada, where more than three-fourths of expected ballots have been cast, Democrats also lead, 42% to 36%.
Without victories in Florida and Nevada, Mr Trump's path to 270 electoral votes would be exceedingly narrow. He already must win nearly all of the roughly dozen battleground states.