Millions of Americans are voting in an historic election that could put Donald Trump back into the White House or make Kamala Harris the first woman to become US president.
The two candidates are neck and neck in the polls after bitter campaign that saw two assassination attempts against Republican Mr Trump as well as the shock withdrawal of President Joe Biden.
In around 100 days, Ms Harris has found her feet and mounted a fierce challenge to her opponent.
With just hours left before polls close, the election has come down to the wire and could be decided by a handful of crucial battleground states.
The first ballots cast on Tuesday mirrored the national divide. Overnight, the six registered voters in the tiny hamlet of Dixville Notch, New Hampshire, split their votes between the two candidates in voting just past midnight.
Please use Chrome browser for a more accessible video player
Former President Mr Trump, 78, voted in Palm Beach, Florida, near his Mar-a-Lago club.
Wearing his trademark red “Make America Great Again” baseball cap, he said at the polling station that he was feeling “very confident”.
“I hear we’re doing very well,” he said. “It looks like Republicans have shown up in force.”
Elon Musk, the world’s richest man and Trump donor, said he will watch results unfold with the former president.
In the meantime, Ms Harris, the 60-year-old Democratic vice president, did radio interviews in the battleground states of Pennsylvania, Georgia and North Carolina.
What do the polls say?
Many polls are too tight to call and, with a large margin of error, most experts are refusing to predict the outcome.
Georgia could be among the first battleground to declare, with polls there closing at 7pm local time (midnight UK time). State election officials told Sky News they could have a result as early as 10pm (3am UK time).
Follow Sky News on WhatsApp
Keep up with all the latest news from the UK and around the world by following Sky News
North Carolina could also give an early indication of how the vote is going.
Even so, it could be several days before the US has a definitive result.
An exit poll by conducted today by Sky News’ sister outlet NBC News and other US outlets suggests that democracy is the top issue on the minds of voters as they cast their ballots.
Some 35% of people said it was their most important issue, closely followed by the economy on 31% and with abortion ranked third at 14%.
Voters are not just selecting a president. A number of seats in the House of Representatives and the Senate are up for grabs. In addition, 10 states will hold abortion-related ballots, half of which would overturn existing restrictions.