The speed and scale of the victory crashed over Barack Obama's die-hard supporters like a tidal wave, unleashing joy and relief after a tense and often ill-tempered campaign.
From a ballroom in Chicago to the plaza outside the White House, in the storm-washed streets of New York and in front of televisions across the nation, Obama's partisans cheered, danced and sang as their hero won another term.
"I feel like I've changed the world! I did something with my life and it changed the world," declared Jane Schumann, 23, who worked in the campaign's digital division, at a convention center in Chicago.
"I'm so proud of my president, words cannot express it. America believes in him," she gushed, as US flags waved by supporters created a sea of red, white and blue, and the intense emotions caused at least two supporters to collapse.
In the run-up to the vote, polls had suggested a tight race and many had expected a long wait for clear results. But as the map of swing states fell to a blue tide of Obama wins, parties erupted in the Democratic half of America.
In Washington, crowds converged on the White House, dancing jigs on their cars and chanting "Four more years!" Crowds poured into New York's iconic Times Square, happy once more after last week's devastating storm swamped the city.
The brief but respectful concession speech by Obama's defeated Republican rival Mitt Romney was greeted with dismissive waves by the crowd at the Chicago victory party, but the mood was more celebratory than condemnatory.
Paul Eberly, 52, and his daughter Sydney, 14, rushed into McCormick Place to take their spot in front of Obama's stage after the results were announced.
"This is a historic election," Paul declared, beaming with joy. "It feels amazing to be around all these people fighting for one cause," Sydney added as she held her father's hand.Bill Millet, 54, had trouble expressing himself.
"I'm so full of joy, I can't describe it," said the computer engineer, who volunteered more than 400 hours of his time for the campaign. "We were expecting it to take a really long time. That's why we're late."
Judy Savage, 58, had to be escorted out of the crowd to get some air after she started to feel dizzy. But she was determined to stick it out so her grandson could hear Obama's speech.
"I'm ecstatic," Savage said after she sipped some water. She had spent hours volunteering for the campaign in Wisconsin and gave a hearty cheer when it fell into Obama's column.
She was in Grant Park for Obama's victory speech in 2008 and said seeing him re-elected meant a lot. "Four years ago I was surprised. This year I was relieved.
Her 12-year-old grandson Jay clutched the entry pass he planned to show off at school -- "if I go tomorrow" -- and treasure forever.
Supporters cheered and several wiped away tears as Obama took to the stage for his victory speech, accompanied by his popular wife Michelle and daughters Sasha and Malia.
"In this election, you, the American people, reminded us that while our road has been hard, while our journey has been long, we have picked ourselves up. We have fought our way back," Obama said.
"We know in our hearts that for the United States of America the best is yet to come."
Not everyone was happy. As might be expected, Romney's conservative and Republican supporters were crushed by the size of the electoral college victory, but some on the left were also underwhelmed.
On the edge of the cheery crowd in New York, a small group of activists from the anti-capitalist movement Occupy Wall Street chanted: "We want real change."
"Obama is the lesser of two evils. But it won't make much difference, when you have a political system dominated by money," said student activist Jesse Marcus, after a record-breaking campaign season that cost $6 billion.
But back in Chicago, Vanessa Cardenas, 37, was optimistic about Obama's second four-year term.
"The coalition he's been able to bring together, the diversity of the crowd and his supporters, I think it bodes well for the country," said Cardenas, who works for a non-profit.
"I truly believe in the American Dream, and we have to build the infrastructure so it's still there for the next generation."