America is a place where all things are possible and the "dream of our founders" is alive, President-elect Barack Obama said after his victory.
The man who will be the first black President of the United States was cheered by hundreds of thousands of supporters as he walked on to a stage in Chicago with his wife Michelle and young daughters Malia, 10, and Sasha, seven, at his side.
His era-changing victory came as he swept a series of key battleground states, winning Virginia, Pennsylvania and Ohio.
"We are, and always will be, the United States of America," he said.
He said it was time to put "hands on the arc of history and bend it once more to the hope of a better day.
"It's been a long time coming but tonight, because of what we did on this day, in this election, at this defining moment, change has come to America," Mr Obama said.
He said he had received an "extraordinarily gracious" call from his Republican rival John McCain, who he said had "fought long and hard" for this campaign and for his country.
"We are better off for the service rendered by this brave and selfless leader," he said of the former Vietnam prisoner of war.
"I congratulate him, I congratulate governor (Sarah) Palin for all that they've achieved.
"And I look forward to working with them to renew this nation's promise in the month's ahead."
