Jubilation stretched into the early morning today in Washington, where a large crowd paraded on Pennsylvania Avenue with drums, balloons and a life-size cutout of Obama.
By 4 a.m., a few young revelers lingered among the reviewing stands being built for January's presidential inauguration.
"I heard that he won and I instinctively came here," said Hollis Gentry, 45, who lives about six blocks away. "I came down here to make a prayer ... that we'll be able to change the nation and the world."
In New York City's Harlem neighborhood, Thomasina Wright started today with a smile. "I'm way happy," she said. "It means that I can tell my seven grandchildren that they have a chance to be president."
"I have hope for several reasons. I hope for everybody including my nephews. They can have a higher rank in America," souvenir vendor and Senegalese immigrant Ibrahim Sisse said today as he was laying out his wares on a Harlem street. "I hope for America, changing."
Earlier, in Detroit, carloads of celebrants rolled past the bronze sculpture of prizefighter Joe Louis' fist, blaring their horns and chanting "Obama!" out of open windows.
"The history, the struggle, it's been a long time," said Cheryl Stephenson, 48. "People are hurting, not just black people. I think we're ready to take a chance.
"We went from 'Yes, we can' to 'Yes, we did.'"
Sarah Geels wept big, slow tears at an Obama victory celebration in St. Louis.
"It's overwhelming," said Geels, 32, a community college librarian. "I just can't believe it. It's too good to be true. There soon will be a drastic improvement in this country."
In Philadelphia, thousands of blacks and whites converged at City Hall shortly after Obama was declared the winner. Under light rain, they danced to the music blaring from car radios. Drivers stopped in the middle of the street, opened their car doors and broadcast Obama's acceptance speech.
"Barack is in the house!" shouted Pamela Williams, 46. "This is very important to me. Change is about to happen."
At Sadiki's restaurant in Philadelphia, the celebration poured out onto the sidewalk.
"Our parents left this planet thinking that we would never, ever see this day, when an African-American could be elected by all the people to the highest seat in the land," said Bernard Smalley Sr. His wife, Jacquelyn, wept.
The celebrations were both large big and small, but the sentiment was the same -- pure joy over how far the country has come. People honked horns, high-fived each other and embraced.
"I was born in the civil rights time. To see this happening is unbelievable. We've got the first black president. A black president!" said Mike Louis, a 53-year-old black man who got teary-eyed as he watched the election results on a giant video board in Cincinnati's Fountain Square. "It's not cured now, but this is a step to curing this country of racism. This is a big, giant step toward getting this country together."
Elsewhere, some Americans were wary, but hopeful. In Iowa, Sam Gipple, 60, said he voted for John McCain because he worries Obama lacks the experience he needs to be an effective leader.
"I'd give him a chance, and hope he keeps some of the good promises he made," said Gipple, the transportation director for Iowa County.
Raymond Stroud, 63, of Little Rock, Ark., considers himself a conservative and supported McCain -- barely. He called the Republican "probably the lesser of two evils."
But in Cleveland, Obama supporters were ready to celebrate. Some gathered at a house party and held champagne flutes above their heads for a toast. "To the first African-American president in the history of the United States!" they shouted.
In Chicago, Obama's hometown, an estimated 125,000 people gathered in unusually warm weather to greet the senator at a delirious victory rally at Grant Park.
"It's fantastic," said Hulon Johnson, 71, a retired Chicago public school principal. "I've always told my kids this was possible; now they'll have to believe me."
LaKeisha Williams, a 27-year-old laid-off school nurse, watched Obama's victory on a TV in a downtown Kansas City concert hall.
"People actually have finally come together and realized that no matter what his race is, he was the right person for the job," she said. "I think it was destiny for him to win. But now we still have to come together to make sure things work."
In Miami's predominantly black Liberty City neighborhood, Otoria Pitts, 30, suggested the significance of Obama's victory goes beyond race.
"His election speaks volumes for a bunch of people," she said. "Children of single mothers, people who put themselves through college. It says, you can do it, you can do it."
Joined by her sister, Susan, and niece, Akira, the three women bought a few rockets from a fireworks stand and lit up the night sky with color.
On the other side of the country, others were thinking how Obama's election could change their lives.
"I'm ecstatic," said Jason Samm, a 33-year-old business owner who was celebrating in South Los Angeles. "I have three kids, which means a lot of doors opening up for them."
Obama's victory also brought back memories of hard-fought battles of generations past.
At Atlanta's Ebenezer Baptist Church, where the Rev. Martin Luther King Jr. preached, Rep. John Lewis, a civil rights hero, said he was hardly able to believe that, 40 years after he was left beaten and bloody on an Alabama bridge as he marched for the right for blacks to vote, he had cast a ballot for Obama.
"This is a great night," he said. "It is an unbelievable night. It is a night of thanksgiving."
As the news of a projected Obama victory flashed across a TV screen, men in the nearly all-black crowd pumped their fists and bowed their heads. Women wept and embraced their children. Screams of "Thank you, Lord!" were heard throughout the sanctuary.
Surveying the scene, Mattie Bridgewater whispered from her seat, "I just can't believe it. Not in my lifetime."
The teacher said she went to the same elementary school as Emmett Till, the boy from Chicago whose murder in Mississippi was one of the catalysts of the civil rights movement. Both she and her 92-year-old mother voted for Obama.
"I'm sitting here in awe," she said. "This is a moment in history that I just thank my God I was allowed to live long enough to see. Now, when I tell my students they can be anything they want to be, that includes president of the United States."
Editor's note: Tom Withers in Cleveland; David Caruso and Verena Dobnik in New York; Kathy Matheson in Philadelphia; Errin Haines in Atlanta; Corey Williams in Detroit; Christina Hoag in Los Angeles; Joe Kay in Cincinnati; Andale Gross in Kansas City; Ron Powers, Brian Westley, and Kamala Lane in Washington; and Tamara Lush in Miami contributed to this story.