Supporters of Joe Biden danced in the streets outside a ballot-counting centre in Philadelphia last night as tallies showed the Democrat could soon be declared winner.
In Detroit, several hundred supporters of President Donald Trump, some armed with guns, raised chants of "we won" outside a counting centre, despite it looking unlikely that this would prove true.
Philadelphia appeared to relish being the centre of attention, even if it was earned only by the relative slowness of its vote counting as the biggest city in the state of Pennsylvania.
It is one of a handful of pivotal states where the outcome of Tuesday's presidential election was still too close to call.
Sean Truppo, a 37-year-old teacher, said he lit fireworks when he heard Mr Biden had overtaken Mr Trump in the state's count before bringing his four-year-old daughter to join the crowds outside the Philadelphia Convention Centre.
"My daughter was born under Trump and I wanted her to witness the end of Trump," he said.
Mr Biden has a 264 to 214 lead in the state-by-state Electoral College vote that determines the winner.
Winning Pennsylvania's 20 electoral votes would put the former vice president over the 270 he needs to secure the presidency.
The nation has spent more than two days waiting for poll workers to canvas millions of votes in a handful of states.
Many Americans have passed that time staring at the slow crawl of developments on the news, or finding ways to distract themselves from the uncertainty.
A few, however, have taken to the streets, with Mr Biden's supporters cheering for poll workers to "count every vote", at times breaking into dance.
Some supporters of Mr Trump, taking a cue from the president, insisted there must be something wrong with any count that showed Biden winning, and brought guns with them to rallies in Detroit and Phoenix.
Dressed in the Trump-supporter uniform of 'Make America Great Again' red baseball hats, some fell to their knees in public prayer.
Gary Smith (69), a registered nurse, attended a rally outside Detroit's counting centre, dressed in a T-shirt that said: 'Mess with us and you mess with the whole trailer park.'
"There have been a lot of phony votes that have been counted," Mr Smith said, echoing the baseless claims made by Mr Trump during extraordinary scenes at the White House on Thursday evening.
Mr Smith said he wished that most legal mail-in ballots would be deemed illegal.
"We will continue with lawsuits, protests, who knows, maybe civil disobedience," he said.
Studies have found illegitimate ballots to be rare in the state-controlled systems used in US elections, which involve both Democratic and Republican election officials and vote-counting observers from both parties.
In Arizona, another closely contested state, a crowd of several hundred of Mr Trump's supporters gathered in Phoenix yesterday morning to wait for the outcome.
There were still some 142,000 ballots to be counted there after a record-breaking wave of early voting resulting from the coronavirus pandemic.
Overnight in New York City, police pushed and shoved protesters, reporters and at least one elected official as they made arrests and tried to move demonstrations out of roadways.