It was the night that the chants went from "Yes, we can" to "Yes, we did."

Barack Obama delivered a historic victory speech after voters elected him the first African-American president of the United States, saying that America has a tough road ahead but 'I have never been more hopeful than I am tonight."

Obama took the stage with his family before more than 125,000 exuberant supporters in Chicago's Grant Park shortly before midnight ET.

"If there is anyone out there who still doubts America is a place where all things are possible, who still wonders if the dream of our founders is alive in our time, who still questions the power of democracy, tonight is your answer," Obama said.

"It's the answer told by lines that stretched around schools and churches, in numbers this nation has never seen, by people who waited for three hours, four hours - many for the first time in their lives - because they believed that this time must be different, and their voices could be that difference.

"At this defining moment, change has come to America."

Obama did not shy away from the challenges facing his nation.

"The greatest of a lifetime," he called them, "two wars, a planet in peril, the worst financial crisis in a century."

He added, "There are many who won't agree with every decision or policy I make as president, and we know that government can't solve every problem. But I will always be honest with you about the challenges we face."

Obama thanked his supporters, saying that his victory belonged to them.

"You did it because you understand the enormity of the task ahead."

Obama eloquently praised his family, calling his wife, Michelle Obama, his best friend and the "love of my life."

For his two young daughters, "You have earned the new puppy that is coming with us to the White House," he added.

Shortly after 11 p.m. ET, Republican John McCain phoned Obama to concede the election.

Obama told his supporters the call was "extraordinary gracious."

Obama's victory is an incredible watershed moment for the country, and the ultimate success of the civil rights movement of the 1960s, when Martin Luther King Jr. dreamed of a future when whites and blacks could live as equals.

"We have come to the end of a long journey. The American people have spoken and they have spoken clearly," McCain told supporters in Arizona in his concession speech. "Senator Obama has achieved a great thing for himself and his country."

McCain spoke graciously of the importance of Obama's win to African-Americans and the U.S. He also offered his sympathy to Obama for the passing of his grandmother just hours before Election Day.

"In a contest as long and difficult as this campaign has been, his success alone commands my respect for his ability and perseverance. But that he managed to do so by inspiring the hopes of so many millions of Americans, who had once wrongly believed they had little at stake, or little influence in the election of an American president, is something I deeply admire and commend him for achieving," McCain said.

Deeply unpopular outgoing U.S. President George W. Bush called Obama to congratulate him on the win, saying "What an awesome night for you, your family and your supporters."

To win the presidency, a candidate must get 270 votes from the Electoral College, which are awarded for winning the popular vote in a state. Obama won in a landslide, taking more than 338 votes even as several battlegrounds states were too close to call.

Obama also had a significant lead in the popular vote, leading McCain by more than four million votes with many more to count. It was a historic turnout with more than a 100-million Americans turning out to vote.

Current results:

• Obama - 338

• McCain - 159

After Obama, a 47-year-old first-term senator from Illinois, won the Democratic nomination, he found himself squaring off against John McCain, 72, a veteran lawmaker and war hero who spent five-and-a-half years as a military prisoner in Vietnam.

McCain struggled to separate himself from the current Bush government, whose approval ratings have plummeted to roughly 25 per cent.

McCain sold himself as a "maverick," frequently using the word in speeches and interviews, and said he would break from the Bush administration and shake up Washington. He also said he was the best candidate to tackle tough foreign policy issues, especially Iraq and the so-called "war on terror."

Obama ran on a campaign of hope and change, saying Americans were fed up with Bush's failed economic policies, a seemingly never-ending war in Iraq and an eroding of civil liberties. He said McCain would essentially bring another four years of the same.

On Tuesday, Obama took an early lead and before 10 p.m. ET he had won the key battleground state of Ohio, which no Republican has ever lost in modern times and still managed to secure the White House.

He later won the Republican states of Florida and Indiana, a state which no Democrat had managed to secure since Lyndon Johnson in 1964.

Obama also won 21 electoral votes in Pennsylvania, where McCain had focused much of his efforts in the final days of his campaign.

Democrats win Senate majority

Democrats have picked up several senate seats from the Republicans, including a win over Sen. Elizabeth Dole in North Carolina. In a controversial attack ad, she had suggested her rival, who teaches Sunday school, was an atheist.

In other senate races:

• Former governor Mark Warner won a seat for the Democrats in Virginia, a traditional Republican stronghold

• Democrat Jeanne Shaheen won in New Hampshire, formerly held by the Republicans

• Democrat Thomas Udall is expected to win a seat from the Republicans in New Mexico

The Democrats increased their effective majority to at least 56 seats in the 100-member Senate.

Who is leading in which states:

• Georgia - 15 - McCain

• Indiana - 11 - Obama

• Kentucky - 8 - McCain

• South Carolina - 8 - McCain

• Vermont - 3 - Obama

• West Virginia - 5 - McCain

• Virginia - 13 - Obama

• North Carolina - 15 - undecided

• Ohio - 20 - Obama

• Connecticut - 7 - Obama

• Delaware - 3 - Obama

• Maine - 4 - Obama 3, McCain 1

• Maryland - 10 - Obama

• Massachusetts - 12- Obama  

• New Jersey - 15 - Obama

• Tennessee - 11 - McCain

• Oklahoma - 7 - McCain

• Arkansas - 6 - McCain

• Alabama - 9 - McCain

• Florida - 27 - Obama

• Illinois - 21 - Obama

• Mississippi - 6 - McCain

• Missouri - 11 - undecided

• New Hampshire - 4 - Obama

• Pennsylvania - 21 - Obama

• District of Columbia - 3 - Obama

• South Dakota - 3 - McCain

• Arizona - 10 - McCain

• Colorado - 9 - McCain

• Rhode Island - 4 - Obama

• Louisiana - 9 - McCain

• Michigan - 17 - Obama

• Wyoming - 3 - McCain

• Minnesota - 10 - Obama

• New Mexico - 5 - Obama

• North Dakota - 3 - McCain

• New York - 31 - Obama

• Texas - 34 - McCain

• Wisconsin - 10 - Obama

• Kansas - 6 - McCain

• Nebraska - 5 - McCain

• Iowa - 7 - Obama

• Utah - 5 - McCain

• Oregon - 7 - Obama

• California - 55 - Obama

• Idaho - 4 - McCain

• Hawaii - 4 - Obama

• Montana - 3 - McCain

• Alaska - 3 - McCain

• Nevada - 5 - Obama

• Washington - 11 - Obama