An official Pennsylvania ballot return envelope is seen, Tuesday, Oct. 2, 2024 in Pa. (Associated Press)

HARRISBURG, Pa. — Voting has begun in earnest in the presidential battleground state of Pennsylvania, as counties increasingly begin mailing out ballots, offering over-the-counter voting in election offices and opening other avenues to voting.

In Philadelphia, the state's largest city, voters have returned about 15,000 mail-in ballots, said Seth Bluestein, who sits on the city's three-member election commission. That's about 10% of the 150,000 ballots that were already mailed, Bluestein said.

Meanwhile, the city has opened seven of 10 planned satellite election offices to operate seven days a week.

Allegheny County, home to Pittsburgh, began hosting over-the-counter voting in the lobby of the county office building on Monday and said people who applied for mail-in ballots have started receiving them in the mail this week.

Montgomery County, the state's third-most populous county, has started mailing out ballots and, on Friday, it will open eight satellite election offices where people can register to vote, apply for a mail-in ballot or complete a mail-in ballot on the spot. On Saturday, Montgomery County is planning to launch a mobile voter services van.

In Centre County, the elections board voted to open a satellite election office on Penn State's campus.

The Department of State lists 20 counties where ballots are available. That includes Union County, where Commissioner Jeff Reber said over-the-counter voting began Monday and mail-in ballots should go into the mail on Friday from the county's printing vendor.

All told, more than 1.45 million voters have applied for a mail-in ballot ahead of the Nov. 5 election, according to data from the Department of State. Of those applicants, Democrats outnumber Republicans by more than two-to-one.

Nearly 9 million people have registered to vote, almost the same number as in 2020's presidential election.