In Maine, independent former Gov. Angus King was elected to succeed retiring GOP Sen. Olympia Snowe. He has not yet said which party he will side with, but Republicans attacked him in television advertising during the race, and Democrats rushed to his cause.
In the presidential race, Obama won in the reliably Democratic Northeast and on the West Coast. Pennsylvania was his, too, despite two late campaign stops by Romney.
Romney won most of the South as well as much of the Rocky Mountain West and Farm Belt.
The president was in Chicago as he awaited the voters' verdict on his four years in office. He told reporters he had a concession speech as well as victory remarks prepared. He congratulated Romney on a spirited campaign. "I know his supporters are just as engaged, just as enthusiastic and working just as hard today" as Obama's own, he added.
Romney reciprocated, congratulating the man who he had campaigned against for more than a year.
Earlier, he raced to Ohio and Pennsylvania for Election Day campaigning and projected confidence as he flew home to Massachusetts. "We fought to the very end, and I think that's why we'll be successful," he said, adding that he had finished writing a speech anticipating victory but nothing if the election went to his rival.
Like Obama, Vice President Joe Biden was in Chicago as he waited to find out if he was in line for a second term. Republican running mate Paul Ryan was with Romney in Boston, although he kept one eye on his campaign for re-election to the House from Wisconsin, a race he won.
The long campaign's cost soared into the billions, much of it spent on negative ads, some harshly so.
In a months-long general election ad war that cost nearly $1 billion, Romney and Republican groups spent more than $550 million and Obama and his allies $381 million, according to organizations that track advertising.