(CNN) — CNN projects that Barack Obama will be the nation’s 44th president.
Obama will address the country from a rally in Chicago, Illinois, later Tuesday night.
The Illinois senator will become the first African-American to win the presidency.
Supporters in Chicago cheering, “Yes, we can” were met with cries of “Yes, we did.”
Obama’s former rival for the Democratic nomination, Sen. Hillary Clinton said in a statement that “we are celebrating an historic victory for the American people.”
“This was a long and hard fought campaign but the result was well worth the wait. Together, under the leadership of President Barack Obama, Vice President Joe Biden, and a Democratic Congress, we will chart a better course to build a new economy and rebuild our leadership in the world.”
The Illinois senator is projected to pick up a big win in Virginia, a state that hasn’t voted for a Democratic president since 1964.
Obama also is projected to beat Sen. John McCain in Ohio, a battleground state that was considered a must-win for the Republican candidate. Watch more on Obama’s Ohio win »
Earlier in the evening, senior McCain aides were growing pessimistic about the Arizona senator’s chances.
Going into the election, national polls showed Obama with an 8-point lead.
In addition to the presidential contest, voters were making choices in a number of key House and Senate races that could determine whether the Democrats strengthen their hold on Congress.
Former Gov. Mark Warner, a Democrat, will win a Senate seat in Virginia, CNN projects. He will replace retiring Republican Sen. John Warner.
Incumbent Sen. Elizabeth Dole, a Republican, is projected to lose her North Carolina seat to Democratic challenger Kay Hagan. Watch Dole concede defeat »
Dole is the wife of 1996 Republican presidential candidate Bob Dole.
CNN also projects Democrats will win two other Senate seats currently held by Republicans. In New Hampshire, former Gov. Jeanne Shaheen will win over incumbent John Sununu, and in New Mexico, Democrat Tom Udall will defeat Republican Steve Pearce.
Senate Minority Leader Mitch McConnell held onto his seat in Kentucky.
Delaware voters re-elected Obama’s running mate, Sen. Joe Biden, to his seventh term. iReport.com: Share your Election Day reaction with CNN
CNN’s Ed Henry said there were lots of long faces in the lobby of the McCain headquarters at the Arizona Biltmore hotel as McCain allies watched returns showing Senate Republicans losing their seats. Watch what McCain says about the race »
Voters expressed excitement and pride in their country after casting their ballots Tuesday in what has proved to be a historic election.
When the ballots are counted, the United States will have elected either its first African-American president or its oldest first-term president and first female vice president.
Poll workers reported high turnout across many parts of the country, and some voters waited hours to cast their ballots. Read about election problems
Reports of minor problems and delays in opening polls began surfacing early Tuesday, shortly after polls opened on the East Coast.
The presidential candidates both voted early in the day before heading out to the campaign trail one last time. Watch Obama family at polls »
Tuesday also marked the end of the longest presidential campaign season in U.S. history — 21 months — and both candidates took the opportunity to make their final pitch to voters.
As McCain and Obama emerged from their parties’ conventions, the race was essentially a toss-up, with McCain campaigning on his experience and Obama on the promise of change. But the race was altered by the financial crisis that hit Wall Street in September. Watch how this election is history in the making »
Although most of the attention has been focused on the presidential race, the outcome of congressional elections across the country will determine whether the Democrats increase their clout on Capitol Hill.
Few predict that the Democrats are in danger of losing their control of either the House or the Senate, but all eyes will be on nearly a dozen close Senate races that are key to whether the Democrats get 60 seats in the Senate.
With 60 votes, Democrats could end any Republican filibusters or other legislative moves to block legislation.
Many political observers also predict that the Democrats could expand their majority in the House.
Voters will also weigh in on a number of ballot initiatives across the country, many of them focused on social issues like abortion and affirmative action