US election day is finally here, and 100 million people have already voted by mail or in person.
Millions more were to vote in person on Tuesday, and the winner -- Republican President Donald Trump or Democratic challenger Joe Biden -- won't be known until the evening at the earliest.
But the battle to achieve a majority 270 electoral votes, earned by winning the popular vote in individual states, has been so close that knowing the winner could spill over into Wednesday or even longer, and result in legal battles over the vote count.
When are the first vote tallies reported?
Numbers start to come in after in-person voting closes at 6:00 pm Eastern Time (EST) (2300 GMT) in parts of two states, and then build as more states stop allowing votes in the hours after.
Most close by 9:00 pm EST, opening the way for a gusher of vote tallies over the following hours, with some districts and states reporting faster than others.
Several, including California, the largest, only close at 11:00 pm EST, and Hawaii and Alaska, small voter-wise, vote until midnight and 1:00 am EST, respectively.
States to watch
Given that opinion polls already indicate clearly which way 38 of the 50 states will go, the focus is on 12 key states.
The first ones to watch are the eastern states of Georgia, where polls close at 7:00 pm; Florida, where, depending on the district, polls shut at 7:00 pm or 8:00 pm; North Carolina where polls close at 7:30 pm; and the western state of Arizona at 8:00 pm EST.
Based on projections for the "decided" states, it is possible that if Biden captures Florida and two of the above others, he could be judged the overall winner of more than 270 electoral college votes early in the night.