Republican Tom Tiffany has raised more than $1 million in his bid for the 7th Congressional District seat in northern Wisconsin, according to a new campaign filing.

Tiffany out-raised his Democratic challenger, Tricia Zunker, with more than $1.2 million since the launch of his campaign in September. He raised $489,000 of that since the end of January, according to his Federal Election Commission filing.

Zunker has raised almost $300,000, including about $153,000 since the end of January, according to her FEC filing.

The two candidates are vying to replace Rep. Sean Duffy, the Republican lawmaker who stepped down at the end of September, forcing the special election. The election will be held on May 12, though Gov. Tony Evers said that he is taking a close look at moving the date of the election.

Tifffany's donations came from 33 different states, including Wisconsin, and Washington D.C. Among Tiffany's donors were Rep. Sean Duffy's campaign, which gave an additional $2,000, bringing the total donation to $4,000, and U.S. Rep. Mike Gallagher's campaign, which also gave $2,000.

Tiffany received money from several political action committees, as well as nearly $175,000 from WinRed, an online fundraising platform created by the Republican Party.

Zunker's donations came largely from within Wisconsin, though some came from California, Washington, Minnesota, Illinois and Colorado. Among her donors was producer Michael Schur, co-creator of the TV show "Parks and Recreation."

She also received more than $115,00 from ActBlue, a technology company that helps gather donations from supporters for Democratic candidates.

The limit for individual contributions to campaigns for the special election is $2,800 for the primary and $2,800 for the special election, according to the FEC. Donors will also be able to commit money to a campaign in the district at the end of 2020 for the general election.

The 7th Congressional District is the largest geographically in Wisconsin, spanning 21 counties plus portions of five others. The district is home to more than 710,000 people, according to census data.

The district is safely Republican, according to J. Miles Coleman, the associate editor of Sabato's Crystal Ball, a publication by the University of Virginia Center for Politics. Voters in the district backed Supreme Court Justice Daniel Kelly in the April 7 election that challenger Jill Karofsky, the candidate favored by Democrats, carried statewide.

But still, Coleman said, there are some positive trends for Democrats in the district. St. Croix County, for example, has started to vote more like some of the blue counties in the Twin Cities metro area, he said.

Zunker, 39, is the president of the Wausau School Board and an associate justice for the Ho-Chunk Nation Supreme Court.

Tiffany, 62, has served as a state senator since 2013 and spent two decades running Wilderness Cruises on the Willow Flowage.

Laura Schulte can be reached at leschulte@gannett.com and twitter.com/SchulteLaura.