At the Montgomery County Board of Elections Office yesterday, there wasn't a single moment when someone wasn't at the counter clutching a voter registration form.
"It's been a madhouse," said Joseph Passarella, the director of voter services, whose office stayed open late - until 8 p.m. - to accommodate the crowds.
At county election boards across the state, lines snaked down hallways as voters rushed to meet last night's deadline for registering to vote in the April 22 primary matchup between Hillary Rodham Clinton and Barack Obama.
According to the Pennsylvania Department of State, 19,639 new voters signed up in the period between March 10 and 17, the latest statewide data available. Of those, 14,256 registered as Democrats.
Also, 29,060 people changed their party affiliation to Democrat in just those seven days.
That increased the total number of eligible Democrats to 4,044,952, an increase of 4 percent from last November.
And those numbers don't reflect the major voter registration push that the Clinton and Obama campaigns waged this past weekend, leading up to yesterday's deadline.
It also doesn't include the crush of applications received by election boards yesterday, many of which added staff and stayed open late to keep up with demand.
"I drove here from Boston," said Emily Person, 28, of West Chester, who had been visiting relatives in Massachusetts.
"I started getting nervous that I wasn't going to make it," added Person, a Republican who is switching parties so she can weigh in on the choice facing Democrats.
"It's been crazy," said James L. Forsythe, head of Chester County's Voter Services, describing the scene at his office yesterday.
Forsythe said his staff had been so busy that he could not hazard a guess about the number of people who stopped at the office. Representatives from Lincoln and West Chester Universities and the Democratic Party came bearing stacks of applications.
In Delaware County, Mary Jo Headley, who has worked 33 years in voter registration - including 10 years as its director - said yesterday's crowd was unprecedented.
"I don't remember a primary ever being like this," she said, adding that the majority of applicants were switching parties. "I've seen a lot of excitement."
The excitement spreads across all age groups, figures released by the state yesterday show. Overall, voters between 45 and 54 beat out their older and younger generations in signing up to vote. Voters between 35 and 44 came in second, with voters between 25 and 34 a close third.
Brendan Gilfillan, a spokesman for the Clinton campaign, put it this way: "We're going after everyone we can get our hands on."
Obama's campaign said an army of volunteers fanned out across the state this past weekend and yesterday to register new voters and lure in people from other parties.
Among those workers: Rick Allen, 63, of Bedminster Township, who yesterday afternoon left his marketing job to staff a voter registration table in Quakertown.
He said he had been hooked on Obama ever since the senator's stirring speech at the Democratic National Convention four years ago. He and his wife have been volunteering regularly to sign up voters.
"My wife is involved even more strongly than I am," Allen said. "She's been manning tables at the Shop 'n Bag in Dublin, Chubby's in Plumsteadville, and at the General Store in Revere."
Despite the last-minute rush, most voter registrations went smoothly yesterday - except at the end of the day in Chester County.
At exactly 4:30 p.m., the lock on the door to Voter Services clicked shut, and a young man pleaded for entry.
"My hand was on the doorknob," he said to no avail.
He was one of about a dozen disgruntled prospective voters who arrived after the scheduled closing time.
Some benefited from the presence of Everett Butcher, a grassroots Obama organizer who was there at closing.
Butcher had made three trips to West Chester yesterday from West Grove, registering about 200 Democrats.
"Don't worry; I can help you," Butcher told the stragglers. "You need to make sure it's postmarked today."
One of the people he helped was Paige Carey, the parent of a senior at Coatesville Area High School. She was carrying 13 new registration forms, and had worked hard to convince her daughter's teenage friends that registering to vote would not somehow get them drafted into the military.
"I really had to ease their fears," she said.