MILWAUKEE — Despite the unseasonably cool 35-degree temperature, lines were already snaking around two sides of the Frank P. Zeidler Municipal Building in downtown Milwaukee by 7:30 a.m., as crowds waited for more than two hours to cast their ballots on the first day of early voting in Wisconsin.

Jon Berlin, 70, a psychiatrist, arrived with his partner, Susan Hrlevich, 60, at 5:20 a.m.

The pair, who are independent voters, wore parkas and brought folding canvas chairs as they walked from their downtown residence to cast votes for Joseph R. Biden Jr. 

They said they feared even longer lines — and exposure to the coronavirus — if they had waited until Nov. 3 to vote. 

“I don’t feel safe in this country for the first time,” said Mr. Berlin. “We have this horrible pandemic and we need a leader who can face the truth and tell the truth.”

Early voting has drawn crowds around the nation, and both campaigns are seeking to turn out their supporters. Senator Kamala Harris of California, Mr. Biden’s running mate, planned to participate in a virtual Milwaukee rally with Senator Tammy Baldwin of Wisconsin and several local officials to encourage early voting there. 

Chrystal Gillon-Mabry, a 68-year-old artist, and her sister, Coral Hegwood, 59, a retired city employee, brought books to read and chairs when they arrived before 5:30 a.m. 

Ms. Hegwood said that she was still undecided as she stood in line. “I don’t want to vote for Trump, but I don’t want to compromise my Christian beliefs,” she said. Afterward, she said she had voted for Mr. Biden. “I prayed and prayed on it,” she said, concluding that “Biden has more compassion than Trump — he has no compassion or empathy for anybody.”

Before in-person early voting began Tuesday, more than 915,000 Wisconsinites had voted since officials began mailing absentee ballots Sept. 17, a figure that amounts to about 30 percent of the state’s total vote in 2016. The turnout has been far higher in the state’s traditionally Democratic strongholds. 

Dane County, which includes Madison and is by far the state’s most Democratic county, has had turnout already that amounts to close to half the votes cast there four years ago. 

No other county’s turnout eclipsed more than 37 percent of its 2016 numbers.

While Wisconsin Democrats have encouraged voters to cast ballots as soon as they are able, the state’s Republican Party urged supporters to wait until early voting began. 

“Avoid the long lines on Election Day,” read a flyer the Republican Party of Wisconsin mailed to supporters last week, urging them to make plans to vote early, which the state describes as voting “absentee” in person. The mailing made no mention of voting by mail.

Denise Williams, 67, who uses a walker and has been staying mostly at home since the pandemic, was glad to socialize — from at least a few feet apart — with fellow voters, all of whom wore masks. She arrived at 6 a.m. and waited almost three hours. 

“Our country is too divided, I want it back together again,” said Ms. Williams, a retired nursing assistant who voted for Mr. Biden. She would have voted by mail, she said, but she never received a ballot. “I wanted to make sure my vote got in, and with my health, I don’t know how I’ll be on Election Day.”

— Kay Nolan and Reid J. Epstein