President Barack Obama rode a wave of broad support from minorities, women and moderates to win re-election Tuesday, defeating Republican challenger Mitt Romney in Democratic strongholds and key battleground states.
Returns put Obama at a projected 303 electoral votes to Romney's 206, giving Obama the 270 electoral votes needed to secure a second term.
Joyful supporters danced and cheered at Obama's victory party in Chicago while the mood at Romney's election-night gathering in Boston was somber.
Governor Mitt Romney conceded the race in a telephone call to the president.
He later spoke to supporters, congratulating the president on his victory and wishing him well in dealing the the challenges facing the nation.
Obama withstood a late push by Romney in Pennsylvania and won battleground states of Ohio, Wisconsin and Iowa, according to CNN projections.
He also easily won traditional Democratic strongholds of California, New York and other populous states such as Michigan and Pennsylvania, where Romney mounted a late but unsuccessful push.
Obama received strong support, as expected, from women voters as well as overwhelming support from African-Americans. He also got strong backing from Hispanic voters, similar to the coalition that carried him to victory four years earlier to make him the nation's first African-American president.
Meanwhile, CNN projected that Democrats will retain their majority in the Senate, ensuring another divided Congress after Republicans earlier were projected to hold their majority in the U.S. House.
Obama and Romney ran dead even in final polls that hinted at a result rivaling some of the closest presidential elections in history, reflecting the deep political chasm in the country.
A heavy turnout was reported in much of the nation, and both campaigns expressed confidence that they would prevail in what was expected to be a long night awaiting results from the eight states still up for grabs that will determine the victor.
As predicted, the election was decided in the battleground states, and as the returns emerged, it became clear that Romney was failing to win enough of them to have a chance.
Obama was projected to win in Virginia, Colorado, Nevada, Ohio, Oregon, California, Washington, Hawaii, New Hampshire, Minnesota, Wisconsin, New Mexico, Pennsylvania, Michigan, New York, Connecticut, Delaware, the District of Columbia, Illinois, Maryland, Massachusetts, Maine, Rhode Island, New Jersey and Vermont, according to ABC, CBS, NBC and other news organizations
Romney won Alaska, North Carolina, Idaho, Missouri, Arizona, Montana, Utah, Wyoming, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, Louisiana, Arkansas, Mississippi, Alabama, Georgia, South Carolina, Tennessee, Kentucky, Indiana and West Virginia, according the same sources.
With the victory, Obama will face the challenge of leading a country facing chronic federal deficits and debt as well as sluggish economic growth in the wake of a devastating recession and financial industry collapse that confronted Obama when he took office in January 2009.
Around the country, voters formed long lines at polling places after record numbers participated in early balloting, indicating a strong turnout.
Sporadic reports of irregularities included malfunctioning voting machines and other problems, including electoral hardships for some struggling to recover from the devastation of Superstorm Sandy in states in the country's northeast.
A judge in Philadelphia, a heavily Democratic city, ordered election officials to cover a mural of Obama at one school used as a polling location after Republicans complained the painting violated election laws.
Elsewhere in the city, GOP poll monitors were being escorted into precincts by sheriff's deputies after some observers had been denied access earlier in the day, said Tasha Jamerson, a spokeswoman for the district attorney's office.
In New Jersey, which permitted electronic balloting in the aftermath of last week's storm, the state chapter of the American Civil Liberties Union headed to court on Tuesday on behalf of voters who said their requests for an electronic ballot weren't being acknowledged.
Candidates usually take Election Day off, but both sides made public appearances even as voting was under way.
Obama visited a local Democratic election center in the Chicago area, while Vice President Joe Biden made "an unannounced but long-scheduled" stop in the key battleground state of Ohio.
Romney and his running mate, Rep. Paul Ryan, also arrived separately in Ohio, with Romney's campaign plane and Air Force Two, which carries the vice president, crossing paths at Cleveland's airport.
Only a handful of states were considered up for grabs and both candidates and their campaigns concluded an exhausting final sprint through them over the weekend and on Monday.
The barnstorming amounted to a montage of Americana electioneering, with Obama and Romney shouting themselves hoarse before boisterous crowds, joined by top surrogates and star power such as Bruce Springsteen singing for Obama and Kid Rock for Romney.