Joe Biden’s victory in Michigan late on Wednesday put the former Democratic vice-president within six electoral college votes of hitting the crucial 270-vote threshold to win the White House.
It significantly narrowed the path for Donald Trump to win re-election, with just four battleground states undeclared, and Mr Biden in striking distance of winning several of them.
In the rustbelt, only Pennsylvania remains in play, while in the south, North Carolina and Georgia are hanging in the balance. Out west, ballots in Nevada are also still being counted.
As of 6.30pm Eastern Standard Time on Wednesday, Mr Biden, the Democratic former US vice-president, had racked up 264 electoral college votes, including 11 from Arizona and 10 from Wisconsin, two states that Mr Trump won in 2016. Mr Trump had 214, after winning 29 votes from the hotly contested state of Florida, according to Associated Press projections.
As the final states tally their remaining votes, here are some possible outcomes.
The Biden campaign has long pinned its hopes on building a “blue wall” across the upper Midwest and rustbelt. Pennsylvania, which has 20 electoral college votes, was always seen as crucial. Now that the Democratic candidate has picked up Michigan’s 16 electoral votes, and 10 in Wisconsin, he can win the White House by picking up Pennsylvania — or any other swing state left on the map.
In Pennsylvania, results are expected to be nail-bitingly close and will be contested. Four years ago, Mr Trump won the state by 44,000 votes, and Michigan by an even narrower margin of just over 10,000 votes.
Long before the polls closed, Democratic and Republican analysts alike said Pennsylvania could prove to be the “tipping point” state, shifting the balance of the electoral college in either candidate’s favour.
As a result, the Trump campaign has also been singularly focused on winning Pennsylvania. Mr Trump will need to maintain his current lead in the “Keystone State” as mail-in votes are counted, and pick up every remaining battleground state, plus Alaska, which has yet to call, if he is going to stay in office.
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