Donald Trump and Joe Biden are locked in a nailbiting race for the presidency with neither side managing to land a knockout blow in the early stages of the contest.
What has become clear is that a Democrat landslide that some polls had been predicting has not materialised and that Donald Trump is outperforming most polls, just like he did in 2016.
With a record 101million Americans voting early or by mail-in ballot, counts in key states like Pennsylvania are expected to take a long time. Delays in Georgia mean it could be days before the full picture becomes clear.
But in the meantime, it will be Democrats who are more nervous than Republicans after several states that appeared to be going Biden's way early on - such as Ohio and North Carolina - began trending to Trump.
Late on Tuesday night Fox News called the swing state of Florida for Trump. If he had lost, it would have made re-election almost impossible. As it stands, it does not knock Biden out of the running, but takes an easy, early victory off the table.
The so-called Rust Belt states - such as Wisconsin, Michigan and Minnesota - now appear vital to a Biden win. Trump flipped these states from Democrat to Republican in 2016, meaning Biden needs to win them back.
Most of those states were trending for Trump in the early stages, but with only about a third of the votes counted.
The first polls closed at 11:00PM GMT on Tuesday. Kentucky was the first state to declare, with its eight electoral college votes going to Trump, shortly followed by Vermont's three to Biden.
By 01:00AM on Wednesday, Virginia had declared for Biden in a race he was expected to win narrowly, while South Carolina went to Trump.
If Biden wins Ohio, it's a sign he could take back the so-called 'blue wall' – a series of states in America's mid-west that had voted reliably Democrat for more than 20 years until Trump carried them in the 2016 election.
Additionally, Ohio has voted with the Electoral College winner in the past 14 presidential elections.
Besides Ohio, the 'blue wall' includes Pennsylvania, Michigan and Wisconsin.
If Biden hold the swing states Hillary Clinton won in 2016 (Nevada, Colorado, New Hampshire, Minnesota) and then put back together the 'blue wall,' he takes the White House.
Trump stunned Democrats when he broke through their wall four years ago. Those victories handed him the Oval Office.
Both candidates focused on those Midwest states in the closing day of the campaign, holding multiple rallies and events there.
Of the battleground states that have yet to be called, Biden has taken the early lead in Ohio, Pennsylvania and North Carolina – three states Clinton lost in 2016.
The Democratic nominee also has taken an early lead in Texas, a state Democrats have argued is starting to trend their way.
Trump, meanwhile, is holding on in Michigan, which he carried for years ago, and taken the early lead in Georgia, a long time red state Democrats were hoping to flip this year.
Mr Biden, 77, entered Election Day as favourite while Mr Trump, playing catch-up in a number of battleground states, has a less likely but still feasible chance of clinching the 270 electoral college votes needed to win out of the 538 up for grabs.
Final polls showed Democrat challenger Mr Biden ahead in most of the key swing states but Trump supporters emerged in large numbers on polling day.
Early results indicated Florida, a must win swing state where polls show the two candidates in a near dead heat, was going to be a nail-biter.
In Pinellas County, which is seen as a bellwether of the state, Mr Biden was up 53 percent to Mr Trump’s 45 percent with 76 percent of the vote counted.
However the early results included mail-in ballots that were expected to favour Mr Biden.
As the night wore on Mr Trump was likely to chip away at that lead.
Indiana, a reliably Republican state, was called for Mr Trump by CNN. The New York Times called Mr Biden as the winner in Vermont, which is not a swing state.
Mr Trump, 74, admitted he probably needed a record turnout to cling on to his presidency but was outwardly confident of upsetting the odds for a second time following his surprise victory four years ago.
It was widely believed that more Democrats had taken advantage of the postal voting system, leaving Mr Trump needing more people to come out on the day.
And the signs on voter numbers were good for him early on, with Florida and Texas – both key swing states –eclipsing their 2016 totals.
Among those voting early was the First Lady, Melania Trump, at a polling station in Palm Beach, Florida – close to the Trumps' Mar-a-Lago residence.
Looking elegant in a £3,500 chain-print Gucci dress, the 50-year-old was also the only person in the vicinity not wearing a mask as she entered the Morton and Barbara Mandel Recreation Centre – although her spokesman argued she was socially distanced.
Asked why she didn't vote alongside the President last week, Mrs Trump said: 'It's Election Day so I wanted to come here to vote today for the election.'
The first result of the day came from the tiny New Hampshire village of Dixville Notch, which prides itself on always being ahead of the rest.
All five villagers who voted plumped for Mr Biden.
However, with some states warning they could take weeks to announce their results due to coronavirus restrictions, there were fears of widespread violence.
The US typically knows the victor long before the results become official as TV networks race to 'call' the election.
Shops and businesses across New York boarded up yesterday fearing protests from both sides if their man was not immediately declared the winner.
And the FBI was investigating reports of scams that saw millions of voters receive automated phone calls telling them to 'stay safe and stay home' instead of voting.
The two candidates each had a frantic final day after a whirlwind week of campaigning.
Mr Trump had got back to the White House at 1am after his final rally in Iowa and fired off a string of tweets before going to bed.
At 7.45am he called into his favoured Fox News, sounding husky and fatigued. Later in the day he appeared at a campaign office in Virginia and said he was feeling 'very good' but admitted his voice was 'choppy'.
The President was due to watch the results come in at the White House, while Mr Biden – aiming to become the oldest US President in history – planned to watch from his home in Delaware.
This article has been adapted from its original source.
