Mark Fazlollah reports:

12:35 p.m.

The turnout stunned election officials in many areas.

"This is big. Real big," said election judge Lowell Webb.

By 11:30 a.m., more than 400 people had already voted at his precinct – just to the north of the University of Pennsylvania and Drexel University. Nearly 200 others, mostly student-age voters, were in line waiting to cast ballots. Compare this to 2004, when 736 voted at the polling site.

Webb said he had worked 35 years as an election official and had never seen a turnout of this magnitude.

The turnout in part was spurred by voter registration drives at the two universities. The precinct registration was more than double 2004 – when Bush received 24 percent of the vote at that polling station.

Precincts across the city told much the same story.

About three miles to the north in a middle-class, high-rise apartment at the northwestern edge of Philadelphia's border with Bala Cynwyd, 140 people had voted before 11 am. In 2004, only 217 voters cast ballots – 79 percent of them Democratic. Election Judge Michaela Hinton-Graham said voters were waiting for her at 6 a.m., an hour before polls opened.

Three hours after the polls opened at a Germantown neighborhood polling site for the Waterview Recreation Center, 402 people from the two precincts casting ballots there had already voted – despite a voting machine breakdown early in the morning, said election clerk Mora Adams.

In the 2004 election, 796 voters cast ballots in the Waterview site – more than 95 percent of them for then-Democratic Presidential candidate John Kerry. Adams said the turnout was the highest she'd seen in the precinct since Philadelphia's first black mayor, W. Wilson Goode, was elected in 1982.