Iowa voters have until 9 p.m. to cast their Election 2012 ballots, but voting in other key swing states ends as much as three hours before then, and exit polling could provide an early indication of whether President Obama or Mitt Romney wins the White House.
The earliest key state to watch for is Virginia, where polls close at 6 p.m. Iowa time.
Voting ends 30 minutes later in swing states Ohio and North Carolina. At 7 p.m. swing states Florida, Pennsylvania and New Hampshire close their polls.
Nevada, the final swing state that could prove as pivotal as Iowa, also closes its voting at 9 p.m.