HARRISBURG — When Kara Rahn, the director of Chester County’s Department of Voter Services, left her office Monday night, about 1,400 online voter registration applications were pending. By the next morning, the number had more than doubled.

Similar scenes played out statewide Tuesday, the last day to register to vote in a state whose 20 electoral votes could be critical in determining the next president.

More than 300,000 voter applications were filed online in the last three weeks, according to the Pennsylvania Department of State. On Monday, an average of 3,200 landed each hour — and the 77,400 for the day marked a record since the state began letting voters register online in August 2015. By midday Tuesday, another 23,000 applications were filed.

“It’s been crazy,” said State Department Spokeswoman Wanda Murren.

Voters also filed paper application forms, and registered through PennDot, so final figures — and whom they might benefit — won’t be clear until the end of the month.

The surge should come as no surprise. Local party organizations on up to the two presidential campaigns held hundreds of registration drives, and efforts intensified over the weekend.

Both presidential nominees have targeted Pennsylvania with visits — with Democrat Hillary Clinton zeroing in on Philadelphia and its suburbs and Republican Donald Trump focused on the state’s conservative center. When they couldn’t appear in person, they flew in high-profile surrogates, from their running mates to movie stars.

The result has been a crush of new registrations and applications from voters seeking to switch their political affiliation or update their personal information.

“I’ve never seen anything quite like this,” said Butler County elections bureau director Shari Brewer.