Hennepin County says it released voter data in error. Republicans are using it to demand more.

Hennepin County elections officials say they mistakenly released data to a Republican state representative who has since used it to allege the county’s voter rolls are problematic.

Rep. Pam Altendorf, R-Red Wing, said earlier this month that she requested and received a voter registration list from Hennepin County that contained voters’ names, addresses, dates of birth and a notation of whether a voter record was active or challenged.

Altendorf, vice co-chair of the House Elections Finance and Government Operations Committee, said her review of that data showed potential discrepancies, like voters with improbable birthdates or missing information and several thousand flagged with a “challenged” status.

“It raises questions about the quality and integrity of our voter data across our state,” she said in a news release. Altendorf was not available to comment.

County officials acknowledged that under state law, they should not have provided the challenge status data to her. They also flatly rejected Altendorf’s claims, saying she has misunderstood the data.

“Hennepin County Elections remains confident in the integrity of its processes and will continue to follow review and audit procedures under state law,” Hennepin County elections officials wrote to county commissioners in a Feb. 13 letter they shared with the Minnesota Star Tribune.

But Republicans are using it to put pressure on state officials to comply with a demand from the federal government to see the state’s entire voter rolls.

President Donald Trump routinely goes even further, pushing for more federal control in elections historically run by state and local governments and alleging without evidence that the election results across the country are rife with fraud.

Altendorf said she is simply pushing for elections to be fair, secure, transparent and accurate. She’s also called on Secretary of State Steve Simon to comply with the U.S. Department of Justice’s demand for the entire state’s voter rolls that has escalated into a lawsuit.

Three of Minnesota’s congressional Republicans mentioned the Hennepin County data in a Feb. 10 letter to U.S. Attorney General Pam Bondi, in which they expressed concern about Simon’s ongoing refusal to hand over statewide data.

Independent elections experts and some Democrats say the federal push to scoop up citizens’ data — from elections and otherwise — violates privacy laws and could discourage people from going to the polls. They also worry that federal officials could use it in unrelated criminal and immigration investigations and as a pretext to interfere with the midterms.

Rep. Emma Greenman, a Minneapolis Democrat who also sits on the House elections committee, likened Altendorf’s disclosure to the conservative YouTuber activist who published a factually dubious video in December alleging fraud in Somali-run day cares in Minneapolis. Federal immigration officials then sent more agents into Minnesota, leading to thousands of arrests and the deaths of two protesters.

Two days after Altendorf requested voter registration lists last fall from four Minnesota counties, Simon’s office sent legal guidance to all counties on what type of data should be disclosed to public officials.

The guidance, which cited state law, said officials, including Altendorf, may receive a “master list” of voter data from counties that has more detailed birthdate data than the standard list available to any member of the public. Neither type of list contains voter registration status, and the law does not require the master list to be shared with public officials; that decision is left to county officials.

Simon’s guidance amounted to interference with her request, Altendorf alleged. Simon’s office told the Star Tribune it was part of “regular communications” with local election officials and otherwise declined to comment.

Altendorf also said she was “shocked” by the level of data the county provided. County officials say they removed most of the data Altendorf could not legally receive but “failed to remove the challenge status” and has put new procedures in place to avoid future errors.

Altendorf said one of her top findings was that nearly 8,000 voter records were marked “challenged” out of more than 800,000 total, including more than 20% in one Minneapolis precinct.

Hennepin County officials, meanwhile, say their data “simply do not” support Altendorf’s allegations of election integrity issues. Challenges are a safeguard routinely used by election administrations to flag eligibility questions that must be answered before a voter can vote, they say, and the vast majority have to do with address verification issues.

The precinct with high rates of challenges that Altendorf singled out covers student housing near the University of Minnesota — a highly mobile population. And some polling place locations changed in the precinct last year, triggering postcard notices to be sent to all voters in the precinct. Any returned card resulted in a challenge on that voter’s record, officials said.

“It is important to note that voters challenged from this precinct does NOT indicate fraud,” county officials wrote in their letter, adding that no people who voted in that precinct in 2025 “were referred to law enforcement for voting twice or for illegally voting.”

Regardless, Altendorf’s allegations have caught the eye of Republican legislative leaders. House GOP Floor Leader Harry Niska, R-Ramsey, mentioned it in a presession news conference this week.