Obama swept to victories in traditionally Democratic states in the East and Midwest, while McCain countered in the safest of Republican territory.
That left the battlegrounds to settle the race: Florida, Ohio, Virginia, Pennsylvania and more. Most of them were customarily Republican, but Obama spent millions hoping to peel away enough to make him the 44th president.
Interviews with voters suggested that almost six in 10 women were backing Obama, and men leaned his way by a narrow margin. Just over half of whites supported McCain, giving him a slim advantage in a group that President Bush carried overwhelmingly in 2004.
The results of The Associated Press survey were based on a preliminary partial sample of nearly 10,000 voters in Election Day polls and in telephone interviews over the past week for early voters.
The same survey showed the economy was by far the top Election Day issue. Six in 10 voters said so, and none of the other top issues - energy, Iraq, terrorism and health care - was picked by more than one in 10.
The AP made its calls of individual states based on surveys of voters as they left the polls.