The letters, reportedly sent Friday by Department of Homeland Security Secretary Markwayne Mullin, asked election officials to work with the agency to determine whether those registrations belong to individuals who are legally eligible to vote.
Federal officials said the comparison relied on publicly available voter registration information combined with immigration records maintained by DHS.
California accounted for the overwhelming majority of the potential matches.
According to the department, 190,832 registrations were flagged in California, while New Jersey recorded 35,152 possible matches. Nevada followed with 15,903 registrations, and Pennsylvania accounted for 14,576.
DHS also stated that many of the records contained matching personal identifiers, including names, dates of birth, residential addresses, and Social Security numbers.
The department said 81,336 California registrations, 19,497 New Jersey registrations, 8,576 Nevada registrations, and 8,594 Pennsylvania registrations matched noncitizen records using Social Security information.
Secretary Mullin emphasized the importance of maintaining accurate voter rolls, saying, “Allowing just one non-citizen to vote cancels the vote of one U.S. citizen.”
The letters reportedly gave each state’s chief election official until July 24 to begin working with DHS on verifying the records.
According to reports, California Secretary of State Shirley Weber, Pennsylvania Secretary of State Al Schmidt, New Jersey Secretary of State Dale Caldwell, and Nevada Secretary of State Francisco Aguilar did not immediately respond to requests for comment.
The Trump administration has argued that the lack of immediate public responses raises additional questions about whether those states intend to cooperate with the federal review.
President Donald Trump also highlighted the issue during a primetime address from the White House, where he discussed election security while announcing the declassification of intelligence documents.
During the speech, Trump said the registrations identified in the four states represented only part of a larger national picture.
According to the administration, 25 states voluntarily participated in a broader DHS review by allowing approximately 68 million voter registrations to be checked through the federal SAVE verification system.
That review reportedly identified approximately 28,000 potential noncitizen registrations.
Administration officials argue that the much larger figure identified in the four states reflects the difficulty of verifying voter rolls when states decline to provide direct access to their registration databases.
Election security has become one of the administration’s top priorities, with officials pointing to long-standing concerns over automatic voter registration systems.
California’s Motor Voter program has received particular attention because individuals applying for driver’s licenses are automatically registered to vote unless they opt out.
Critics have argued that the process creates opportunities for registration mistakes involving individuals who are legally present in the United States but are not American citizens.
State officials have previously acknowledged problems with California’s automatic registration system.
In 2019, the California Department of Motor Vehicles admitted that approximately 1,500 ineligible voters—including noncitizens—had mistakenly been registered through administrative errors before later revising that figure upward.
Although state officials described the issue as a processing mistake and implemented corrective actions, critics argue the incident demonstrated broader vulnerabilities that deserve additional scrutiny.
The Trump administration contends that stronger safeguards are necessary nationwide.
Officials continue to advocate for proof-of-citizenship requirements during voter registration and have supported legislation designed to strengthen election verification standards.
One proposal receiving renewed attention is the SAVE America Act, which would require documentary proof of citizenship and photo identification when registering to vote.
The measure remains pending in the Senate, where supporters continue working to secure enough votes for passage.
Meanwhile, DHS has announced that federal immigration authorities will continue investigating cases involving noncitizens who illegally participate in American elections.
The Department of Justice has also increased enforcement efforts.
According to the administration, prosecutors have already secured roughly two dozen arrests and convictions involving alleged noncitizen voting this year, while approximately 90 additional investigations remain ongoing.
Supporters of the administration say the latest DHS findings demonstrate the importance of continued federal oversight and stronger election safeguards.
Critics, however, maintain that every flagged registration must be individually verified before any conclusions are drawn about voter eligibility.
As the July 24 deadline approaches, attention will remain focused on whether the four states cooperate with DHS and what the verification process ultimately reveals about the flagged voter registrations.
