Millions of Americans are voting in person on Tuesday, adding their ballots to the more than 99 million already cast by early voters in the country’s most divisive contest in decades.
Voters braved long lines and the threat of the coronavirus to cast ballots as they chose between two starkly different visions of America for the next four years.
Donald Trump, 74, is seeking to avoid becoming the first incumbent president to lose a re-election fight since George HW Bush in 1992.
Joe Biden, the Democratic candidate and a career politician, has had a strong and consistent lead in national polls.
But the Republican Trump is close in enough swing states to possibly piece together the 270 state-by-state Electoral College votes needed to hold on to the presidency, which he won in a surprise 2016 election result despite losing the popular vote to Democrat Hillary Clinton by nearly 3 million ballots.
Polls opened in some Eastern states at 6 a.m. EST (1100 GMT). The most closely watched results will start to trickle in after 7 p.m. EST (0000 GMT) when polls close in states such as Georgia.
However, it may be days before the result is known, especially if legal challenges focused on postal ballots are accepted in the event of a tight race.
The voting caps a campaign dominated by the coronavirus pandemic that has killed more than 231,000 people in the United States and put millions out of work. The country has also been shaken by nationwide protests over racial injustice against Black Americans.
Each candidate declared the other fundamentally unfit to lead a nation grappling with COVID-19 and facing foundational questions about racial justice and economic fairness.
Although more than 99 million Americans have already voted in early, in-person voting or by mail, Election Day marks a deadline for votes to be cast and still serves as a ritual for those who go to the polls on the first Tuesday after the first Monday in November.
Trump has questioned the integrity of the election results for months, making unsubstantiated claims that mail-in voting is rife with fraud and refusing to commit to a peaceful transfer of power if he loses.
The president has also said votes should only be counted through election night, even though many states often take days or weeks to tally ballots.
Results in Florida, where mail-in ballots can be counted before Election Day, are expected to begin to come in relatively quickly on Tuesday night.
But Pennsylvania, Michigan and Wisconsin will not begin counting the flood of mail ballots until Election Day, raising the possibility of a prolonged vote count that could stretch for several days.
Record early voting has been fuelled by the pandemic and the US is on course for its highest electoral turnout in more than a century.