The dizzying presidential contest between Democrat Kamala Harris and Republican Donald Trump hurtled toward an uncertain finish as millions of American voters waited in calm, orderly lines to choose between two sharply different visions for the country.
A race churned by unprecedented events - two assassination attempts against Mr Trump, President Joe Biden's surprise withdrawal and Ms Harris' rapid rise - remained neck and neck after billions of dollars in spending and months of frenetic campaigning.
Mr Trump, who has frequently spread false claims that he won the 2020 presidential election against Mr Biden and whose supporters attacked the US Capitol on 6 January 2021, voted near his home in Palm Beach, Florida.
"If I lose an election, if it's a fair election, I'm gonna be the first one to acknowledge it," Mr Trump told reporters.
Ms Harris, who had earlier sent in her ballot by mail to her home state of California, took part in radio interviews, encouraging listeners to vote.
The US Vice President was due to address students at Howard University, a historically black college in Washington DC where she was an undergraduate.
"To go back tonight to Howard University, my beloved alma mater, and be able to hopefully recognize this day for what it is, is really full circle for me," Ms Harris said on a radio interview.
More than 80 million Americans had voted before polling day, either via mail or in person, and lines at many polling stations on election day were short and orderly.
In Dearborn, Michigan, Nakita Hogue, 50, was joined by her 18-year-old college student daughter, Niemah Hogue, to vote for Ms Harris.
Niemah said she takes birth control to help regulate her period, while her mother recalled needing surgery after she had a miscarriage in her 20s, and both feared efforts by Republican politicians to restrict reproductive healthcare.
"For my daughter, who is going out into the world and making her own way, I want her to have that choice," Nakita Hogue said.
"She should be able to make her own decisions."
(Above: Trump dances on stage at rally in Michigan)
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At a library in Phoenix, Arizona, Felicia Navajo, 34, and her husband Jesse Miranda, 52, arrived with one of their three young children to vote for Mr Trump.
Mr Miranda, a union plumber, immigrated to the US from Mexico when he was four years old, and said he believed Mr Trump would do a better job of fighting inflation and controlling immigration.
"I want to see good people come to this town, people that are willing to work, people who are willing to just live the American dream," Mr Miranda said.
Hoaxes and glitches
Some glitches of vote-counting technology were reported in Cambria County, Pennsylvania, and a local court agreed to extend voting hours by two hours.
Hoax bomb threats, many of which appeared to originate from Russian email domains, were directed at polling locations in three battleground states - Georgia, Michigan and Wisconsin - as voting was underway, the FBI said.
None of the threats were immediately determined to be credible, it said.
Mr Trump's campaign has suggested he may declare victory on election night even while millions of ballots have yet to be counted, as he did four years ago.
The former president has repeatedly claimed any defeat could only stem from widespread fraud, echoing his false claims from 2020.
The winner may not be known for days if the margins in battleground states are as slim as expected.
(Above: Oprah Winfrey welcomes Harris on stage at final rally in Pennsylvania)
No matter who wins, history will be made.
Ms Harris, 60, the first female vice president, would become the first woman, black woman and South Asian American to win the presidency.
While Mr Trump, 78, the only president to be impeached twice and the first former president to be criminally convicted, would also become the first president to win non-consecutive terms in more than a century.
Opinion polls show the candidates running neck and neck in each of the seven states likely to determine the winner: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.
Reuters/Ipsos polling shows Ms Harris leading among women by 12 percentage points and Mr Trump winning among men by seven percentage points.
The contest reflects a deeply polarised nation whose divisions have only grown starker during a fiercely competitive race.
Mr Trump has employed increasingly dark and apocalyptic rhetoric on the campaign trail.
Ms Harris has urged Americans to come together, warning that a second Trump term would threaten the underpinnings of American democracy.
Control of both chambers of Congress is also up for grabs.
Republicans have an easier path in the US Senate, where Democrats are defending several seats in Republican-leaning states, while the House of Representatives looks like a toss-up.
Dark rhetoric
During the campaign, Mr Trump hammered first Mr Biden and then Ms Harris for their handling of the economy, which polls show is at the top of voters' concerns despite low unemployment and cooling inflation.
However, he showed a characteristic inability to stay on message, at one point questioning Ms Harris' black identity and vowing to protect women "whether they like it or not."
Even more than in 2016 and 2020, Mr Trump has demonised immigrants who crossed the border illegally, falsely accusing them of fomenting a violent crime wave, and he has vowed to use the government to prosecute his political rivals.
Ms Harris has sought to piece together a broader coalition of liberal Democrats, independents and disaffected moderate Republicans, describing Mr Trump as too dangerous to elect.
She campaigned on protecting reproductive rights, an issue that has galvanised women since the US Supreme Court in 2022 eliminated a nationwide right to abortion.
Ms Harris has faced anger from many pro-Palestinian voters over the Biden administration's military and financial support for Israel's war in Gaza.
While she has not previewed a shift in US policy, she has said she will do everything possible to end the conflict.
After Mr Biden, 81, withdrew amid concerns about his age and mental ability, Ms Harris sought to turn the tables on Mr Trump, pointing to his rambling rallies as evidence he is unfit, and has tried to court young voters, seen as a critical voting bloc.
Mr Trump countered the likes of MS Harris supporters Taylor Swift and Beyoncé with Elon Musk, the world's richest man, who played an increasingly visible role as a surrogate and a top donor to Mr Trump's cause.
Mr Musk was expected to spend election night with Mr Trump at the former president's home in Florida.
The vote follows one of the most turbulent half-years in modern American politics.
In May, a New York jury found Mr Trump guilty of falsifying business records to hide hush money payments to an adult film actress.
Four weeks later, Mr Trump and Mr Biden met for their only debate, where the incumbent president delivered a disastrous performance that supercharged voters' existing concerns about his mental acuity.
In July, Mr Trump narrowly escaped a would-be assassin's bullet at a Pennsylvania rally. Barely a week later, Mr Biden exited the race.
