A large crowd turned up outside a polling station near Mrs Hillary Clinton's hometown of Chappaqua, New York, to greet the Democratic nominee as she headed in to cast her vote yesterday.
She turned up with her husband, former president Bill Clinton, to cast their votes early in the morning and told reporters that it was a "humbling feeling".
"I know how much responsibility goes with this and so many people are counting on the outcome of this election, what it means for our country, and I will do the very best I can if I'm fortunate enough to win today," she said.
A crowd had also gathered in New York City at the polling station near Trump Tower, where Mr Trump was due to cast his vote.
Election Day began with excitement across the country yesterday with many polling stations reporting above-average activity.
"We opened up at 6.30 in the morning and we had a line from our door all the way down to our gym," said Ms Barbara Lustig Jr, 48, the polling location coordinator at the Brecksville Community Centre in Ohio, where a line stretched more than 100m.
One of the voters in line, physical therapist Luke Halliwell, 48, said he was voting for Republican nominee Mr Trump because of immigration and who gets to appoint judges to the Supreme Court. "I would like the word illegal alien to actually mean something," he said.
In New York, housewife Grace Yang, 47, was one of those who turned up shortly after polling stations opened to cast her vote. She had been living in Paris for the past two months but flew back to the US for two days just to vote.
"This election is historic, and I wanted to vote for Hillary. Donald Trump is just unacceptable," said Ms Yang, who had been staying up till 3am in Paris just to catch all the presidential debates.
New York is the focus for many as this is the home state of both candidates and both have large events planned in the city.
On Monday, there were already demonstrators gathered outside Trump Tower on Fifth Avenue, both for and against Mr Trump.
New Jersey voter Karen Arakelian, 62, who owns a furniture business said she was certain Mr Trump was the right person to lead the country.
"He's not owned by anybody. He also doesn't need this job. The only reason he is doing it is because he sees the country is in trouble," said Ms Arakelian.
But others like educator Kyle Haver, 59, who was chanting "no Trump, stop Trump", said: "Trump is dangerous to global society, does not understand civics or democracy and only serves himself."
Yesterday, there were also some Election Day rituals taking place.
In Washington, President Barack Obama spent the morning playing basketball at the gym of Fort Lesley McNair, something he has been doing on Election Day since his own campaign for president.
The last polls were due to close late yesterday (late this morning, Singapore time). The winners in the last three elections were declared between 11pm and 11.30pm (noon and 12.30pm Singapore time).
On Monday, workers had been busy putting the finishing touches on the two venues in New York where victory parties by the two candidates have been planned. Mr Trump has booked a large ballroom in the Hilton Hotel that is walking distance from Trump Tower.
Mrs Clinton, meanwhile, will hold her election night party at the main lobby of the Jacob K. Javits Convention Centre. The choice to hold the event in the futuristically designed centre means that if Mrs Clinton wins, she will be claiming victory standing under a glass ceiling.
• Additional reporting by Paul Zach in Cleveland, Ohio