Polls have closed in all seven key battlegrounds of this US election.
The result of two swing states have already been projected, and there are signs to suggest how others are leaning.
But it could still be some time before we find out whether Republican Donald Trump or Democrat Kamala Harris has won.
Results are declared state-by-state, and the BBC is keeping you updated with a running tally as we go.
What is happening in the battleground swing states?
The race will come down to results from seven swing states, which before election day experts believed either Harris or Trump could win.
Turnout has been high in early voting, both in-person and by mail, with records broken in some states.
It’s worth noting that votes are very much still being counted. Nonetheless, there are some signs of how voting in these key states is going.
Right now, as at 00:38 EST (05:38 GMT), Donald Trump is projected to win:
North Carolina, the first swing state to be projected
Georgia, which Democrat Joe Biden narrowly won in 2020
Trump also looks to be ahead in:
Wisconsin, where an overall result may also take some time
The race is very close in:
Pennsylvania, where final results could take some time
Michigan, where a final result is not expected until the end of Wednesday
Arizona, where the overall count could take days
Nevada, where the overall count could also take days
Up-to-the-minute results as they happen
So what does this mean for when the result is expected?
The last polls will close at 01:00 EST (06:00 GMT) early on Wednesday.
In some presidential races, the victor has been named late on election night, or early the next morning.
This time, the knife-edge race in many states could complicate how quickly media outlets project a winner. Narrow victories could also mean recounts.
In the key swing state of Pennsylvania, for example, a recount would be required if there’s a half-percentage-point difference between the votes cast for the winner and loser. In 2020, the margin was just over 1.1 percentage points.
But we are getting projected results from states with the most predictable voting patterns.
How to follow the US election on the BBC
A really simple guide to the presidential vote
Legal challenges are also possible. More than 100 pre-election lawsuits have already been filed, mostly by Republicans challenging voter eligibility and voter roll management.
Counting can take some time, with the verification of ballots requiring comparisons with active voter numbers; removing, unfolding and examining every single ballot for tears, stains or damage; and documenting and investigating any inconsistencies.
On the other hand, vote-counting has sped up in some areas, including the crucial state of Michigan, and fewer votes have been cast by mail than in the last election, which was during the Covid pandemic.
Why should we be cautious of early voting data?
In such a tight race, early vote results may not be the best indication of who will eventually win.
In 2020, Trump was leading in some key states on election night but Biden overtook him as mail ballots, heavily favoured by Democrats at the time, were counted.
Though election experts warned beforehand of such a phenomenon, Trump seized upon it to amplify his unfounded claims that the election was stolen.
There could be another so-called “red mirage” this year – or perhaps a “blue mirage” that initially favours Harris but then shifts toward Trump.
More than 83 million Americans voted early, according to the University of Florida Election Lab’s nationwide early vote tracker.
But while early voting has typically favoured Democrats, registered Republicans have cast nearly as many early votes this time around.
When have previous presidential election results been announced?
In the 2020 election, US TV networks did not declare Joe Biden the winner until four days after election day, when the result in Pennsylvania became clearer.
In other recent elections, voters have had a much shorter wait.
In 2016, Trump was declared the winner shortly before 03:00 EST (08:00 GMT) a few hours after polls closed.
In 2012, when Barack Obama secured a second term, his victory was projected before midnight the same evening of election day.
However, the 2000 election between George W Bush and Al Gore was a notable exception. The race was not decided for five weeks, when the US Supreme Court voted to end Florida’s recount. That kept Bush in place as winner and handed him the White House.
What happens if the presidential election results are challenged?
Once every valid vote has been included in the final results, a process known as the electoral college comes into play.
In each state a varying number of electoral college votes can be won, and it is securing these – and not just the backing of voters themselves – that ultimately wins the presidency.
What is the US electoral college, and how does it work?
How are votes counted in the US election?
Generally, states award all of their electoral college votes to whoever wins the popular vote and this is confirmed after meetings on 17 December.
The new US Congress then meets on 6 January to count the electoral college votes and confirm the new president.
After the 2020 election, Trump refused to concede and rallied supporters to march on the US Capitol as Congress was meeting to certify Biden’s victory.
He urged his Vice-President, Mike Pence, to reject the results – but Pence refused.
Even after the riot was cleared and members of Congress regrouped, 147 Republicans voted unsuccessfully to overturn Trump’s loss.
Electoral reforms since then have made it harder for lawmakers to object to certified results sent to them from individual states.
They have also clarified that the vice-president has no power to unilaterally reject electoral votes.
Nevertheless, election watchers expect that efforts to delay certification of the 2024 vote could take place at the local and state level.
Trump, his running mate JD Vance and top Republican leaders on Capitol Hill have refused on several occasions to state unequivocally that they will accept the results if he loses.
What happens if there is a tie?
It is possible that the two candidates could end up in a tie because they have the same number of electoral college votes – 269 each.
In that situation, members of the House of Representatives – the lower chamber of the US Congress – would vote to choose the president in a process known as a contingent election.
Meanwhile the Senate – the upper chamber – would vote for the vice-president.
But that hasn’t happened for about 200 years.
When is the presidential inauguration?
The president-elect will begin their term in office after being inaugurated on Monday, 20 January 2025, in the grounds of the US Capitol complex.
It will be the 60th presidential inauguration in US history.
The event will see the new president sworn in on a pledge to uphold the Constitution and then deliver their inaugural address.
BBC
