Donald Trump and Joe Biden were facing a tight race in a number of battleground states, according to early results in the divisive presidential election that has been overshadowed by the coronavirus pandemic.
Florida, a state deemed essential for the Republican to remain in the White House, was leaning his way with nearly all of the votes counted.
The race was also tight in the swing states of Georgia, Ohio, Pennsylvania and North Carolina, with the election proving to be a nailbiter as many polls closed across the nation.
There were no upsets in safe states with both men winning predictable victories early in the night.
The Republican took Mississippi, Oklahoma and Alabama, while Mr Biden won in New York, Virginia and his home state of Delaware.
Mr Trump said he believes he has a “very solid chance at winning”, while his Democratic challenger cautiously said he remains “hopeful”.
Mr Biden, a former vice-president, has painted the election as the “battle for the soul” of the nation, saying democracy itself is at stake, while Mr Trump has reprised his “make America great again” mantra.
Economic fairness and racial justice have been key issues and both men have clashed over the Covid-19 response, as the nation reels from more than 230,000 coronavirus deaths in the US and millions more having lost their jobs.
Mr Trump has sought to downplay the pandemic’s effect, saying the nation is “rounding the corner”, while his opponent has accused the president of having surrendered to the disease.
Steady lines of voters flocked to the polls on Tuesday after around 100 million Americans voted early, setting the nation on course for a record turnout figure.
A noticeably hoarse Mr Trump, spoke to Fox News by phone to speak up his “very solid” odds, predicting he could win with a larger margin in electoral college votes than in 2016 against Hillary Clinton.
But, during a later visit to campaign headquarters, he spoke more gravely saying “winning is easy” but “losing is never easy, not for me it’s not”.
Mr Biden, after a last pitch in the crucial state of Pennsylvania, struck a cautious tone, saying that “it’s just so uncertain”.
“I’m superstitious about predicting what an outcome’s gonna be until it happens … but I’m hopeful,” he added.
National polls have consistently put Mr Biden ahead, but the race has been close in the battleground states, including Florida, Ohio and Arizona, which hold the keys to the White House.
Nigel Farage, the Brexit Party leader who has joined Mr Trump on the campaign trail, told the PA news agency that high turnout could be bad news for his ally.
“Obviously, it’s tough to judge. We’re dealing with a huge turnout, unprecedented in modern times. I have memories of the UK referendum, we had a huge turnout and Brexit won.”
Anticipation was building in downtown Washington DC as nervous voters wait for the national picture to become clearer.
As temperatures dropped, some of those gathered on Black Lives Matter Plaza Northwest huddled around a projector showing TV news bringing live updates from across the US.
While the vast majority of the crowd of thousands is made up of Joe Biden supporters, the few Donald Trump fans walk freely while wearing Make America Great Again caps and there was not yet sign of the unrest feared by many.
Bernadette Eichbelberger, a 68-year-old retired health care worker, admitted the wait for results had frayed her nerves.
She said she has spent much of the last week phoning potential voters for Mr Biden and is fearful of what another victory for Mr Trump will mean for the country.
“I’ve been worried for the last year,” she told the PA news agency. “I’ve been sick for the last four years of what he’s done to this country. It would only get worse, we will become a fascist country if he gets elected.”
Each state gets a number of electoral college votes roughly in line with its population, and they largely hand them all to the winner in that state. With 538 up for grabs across the States, 270 is the key number to win the presidency.
But the election night itself may not reveal the definite answer many want, with Mr Trump having refused to commit to a peaceful transition of power and having warned of a “rigged election”.
Along with his attacks, which have largely centred on unfounded claims over postal voting, he has threatened to challenge the result in the courts if it is not in his favour.
The president has invited hundreds of supporters to an election party inside the White House, while Mr Biden will await the results in his hometown of Wilmington, Delaware.