Democratic presidential candidate Joe Biden said the results of the election may not be known until Wednesday morning or later but he is optimistic of the outcome.
Biden, who is locked in a tight race against Republican President Donald Trump, took to the stage at the outdoor venue in Wilmington, Delaware, along with his wife Jill.
"We knew this was going to go long, but who knew we would go into maybe tomorrow morning, maybe even longer!" he said.
"But we feel good about where we are. I'm here to tell you tonight we believe we're on track to win this election."
"It ain't over until every vote, every ballot is counted."