Figures tabulated Wednesday by The Associated Press showed that 114.3 million people had voted with 99 per cent of precincts reporting. However, about 120 million people cast ballots, including 5.5 million to 6 million absentee and provisional ballots yet to be counted, said Curtis Gans, director of the nonpartisan Committee for the Study of the American Electorate.
The 120 million figure represents just under 60 per cent of eligible voters the highest percentage turnout since 1968, Mr. Gans said.
One county clerk in Illinois spoke for poll workers across the country on Election Day when he summed up the turnout with one word: "Gangbusters."
Four years ago, in the election that led to Republican George W. Bush's narrow victory over Democrat Al Gore, slightly more than 54 per cent of eligible voters, or about 105.4 million, voted.
President Bill Clinton's 1996 re-election bid drew just 49 per cent of eligible voters, about 96.3 million. But his 1992 challenge to the first President Bush brought out 55.2 per cent of eligible voters, or about 104.4 million.
Officials had eyes on whether Tuesday's turnout would rival the 1960 benchmark, when about two-thirds of eligible voters came out to back either Democrat John Kennedy or Republican Richard Nixon.
At least six states Alabama, Florida, Georgia, South Carolina, Tennessee and Virginia and the District of Columbia set voter-turnout highs, according to Mr. Gans' analysis. Kentucky initially appeared to set a record for turnout, too, but more analysis showed that was not the case.
"On both sides, the presidency of George Bush was a lightning rod," he said. "For those who supported him, they supported him for traditional values, strong leadership, the war on terrorism and some rejection of things that the Democrats advocate," such as abortion rights and gay civil unions.
"On the other side, it was the war on Iraq, debt, the feeling he hadn't been candid with the American people, too conservative values and division in the country," Mr. Gans said.
When it comes to voting, the United States still has some distance to go to match the participation of voters in other democracies. But by U.S. standards, Tuesday shaped up as an impressive show.
In California, the estimated voter turnout was 12 million, a record for the state.
"It's a landslide of people coming out, which is nice," voter Theresa Cocco, 45, a business owner, said outside the Surfing Museum in Huntington Beach. "It renews my faith in society."