As of 11:00 p.m.
(AP) - Obama wins Nevada, Colorado, Oregon and Wisconsin.
As of 10:45 p.m.
(AP) - The Associated Press is calling the presidential election for Obama after Romney lost Ohio and several other key states.
The Chicago convention center where Obama supporters have gathered to watch the results is exploding in joy and enthusiasm. Not so for the Romney camp in Boston, which has been muted as results increasingly showed the tally of electoral votes rising in Obama's column.
As of 10:15 p.m.
(AP) - Mitt Romney is the winner in North Carolina, where both campaigns had worked to wrap up the state's 15 electoral votes.
While President Barack Obama hadn't returned to North Carolina since the Democratic National Convention in Charlotte, first lady Michelle Obama was in the state Monday and former President Bill Clinton visited on Sunday.
Obama, meanwhile, has won Minnesota, despite a late Republican push in the state. And a win in California has given Obama an additional 55 electoral votes toward the 270 he needs to win a second term in office.
Mitt Romney has won in Arizona, with 11 electoral votes, and also in Idaho. But Romney earlier lost Pennsylvania and New Hampshire, two states in which his campaign had been hoping for a win. Obama has also picked up the four electoral votes from Hawaii.
Obama now has 229 electoral votes to Romney's 190.
As of 10:00 p.m.
(AP) - Obama wins new Mexico; Romney wins Missouri
As of 9:15 p.m.
(AP) - Pennsylvania has turned out to be safe for the Democrats after all. The state's 20 electoral votes are going to President Barack Obama.
Pennsylvania had been considered to be in Obama's column for much of the campaign. But in recent days, as polls appeared to narrow, Mitt Romney's campaign saw an opportunity. There was a late advertising blitz for Romney, and the candidate added visits to Pennsylvania Sunday and again on Election Day.
Voters in Indiana have rejected one of the two Republican Senate candidates whose campaigns ran into trouble because of comments about rape and abortion. Democrat Joe Donnelly defeated Republican Richard Mourdock, who slipped in the polls after saying during a debate that when a woman who is raped becomes pregnant, it's what "God intended."
As of 9:00 p.m.
(AP) - President Barack Obama is the winner of the 16 electoral votes in Michigan - the state that benefited the most from the auto industry bailout. Michigan, where Mitt Romney's father served as governor, wasn't heavily contested by the two campaigns, though it did see some late GOP advertising.
Obama also won in New Jersey, battered last week by Hurricane Sandy.
Romney, meanwhile, has added Alabama's nine electoral votes to his column. Romney also captured the 38 electoral votes at stake in Texas, and added wins in Louisiana, Mississippi, Kansas, South Dakota, North Dakota, Arkansas and Wyoming. He also won at least four of Nebraska's five votes.
Obama won in New York, with 29 electoral votes. At last count, Romney has 153 electoral votes to Obama's 123.
Texans elected Republican Ted Cruz as the state's first Hispanic U.S. senator. Michigan Democratic Sen. Debbie Stabenow won re-election over former U.S. Rep. Peter Hoekstra. Democrats Kirsten Gillibrand in New York and Amy Klobuchar in Minnesota are also staying in their Senate seats. Republican John Barrasso won re-election in Wyoming.
As of 8:00 p.m.
(AP) - Mitt Romney has won in Georgia. It's a state that had appeared to be a potential battleground early in the campaign, but ended up being part of Romney's Southern base.
Romney also added Tennessee's 11 electoral votes to his total, putting him ahead of President Barack Obama so far. Romney has 67 electoral votes so far, to Obama's 64.
Romney had been far ahead of Obama in the polls in Tennessee, with strong support from white evangelical voters. Romney lost his party's primary in Tennessee earlier this year to Rick Santorum.
Tennessee voters also re-elected Republican Sen. Bob Corker.
In Connecticut, Democratic Rep. Chris Murphy has defeated Republican former wrestling executive Linda McMahon in the race for the Senate seat that had been held by retiring independent Joe Lieberman. McMahon spent more than $42 million of her own money on the Senate bid.
As of 7:30 p.m.
(AP) - Mitt Romney has won in Indiana, a state won by President Barack Obama four years ago. Romney is also the winner in South Carolina, a state where Obama is deeply unpopular. Those states have 20 electoral votes between them.
Obama has won his home state of Illinois, as well as Mitt Romney's home state of Massachusetts and Vice President Joe Biden's home state of Delaware.
There have been no surprises in the returns so far from Eastern and Midwestern states. Obama wins the 20 electoral votes in Illinois, and the 11 in Massachusetts, along with 10 in Maryland and Delaware's three. He's also the winner in Connecticut, Rhode Island and the District of Columbia. And in Maine, which splits its electoral votes, Obama has won at least three of the four votes.
Romney won in Oklahoma, with seven electoral votes.
As of 6:30 p.m.
(AP) - Mitt Romney has captured West Virginia and its five electoral votes.
President Barack Obama is unpopular in the state, and West Virginia GOP officials have been hoping that would lead to victories for other Republicans on the ballot.
Romney earlier won in Kentucky, giving him 13 electoral votes overall, while Obama was the winner of Vermont's three electoral votes.