More than 1,600 polling places are open in Arizona for the 2012 general election for offices from president of the United States to local school boards.

More than 3.1 million Arizonans are registered to vote, and Arizona Secretary of State Ken Bennett predicted last week that 75 percent would cast ballots.

Most ballots have already been cast, by mail-in or dropoff. Bennett said he thought nearly 70 percent of Arizonans would vote early.

Voters who still have early ballots in hand must drop them at their county recorder's offices or at any polling place before 7 p.m., when polls close.

On the Arizona ballot are the electors for president, three candidates for U.S. Senate, candidates in all nine congressional districts, candidates for the Corporation Commission, eight proposed constitutional amendments and one citizens initiative, all 90 seats in the Arizona Legislature, county offices, school boards and local ballot measures.

First results are expected from county elections offices and the Secretary of State's office around 8 p.m.