Nearly 150,000 California voters saw their mail-in ballots tossed out during the state’s June primary election — a significant jump from recent election cycles, even as California continues pushing policies designed to make voting easier and ensure every ballot is counted.
California has long been known for its extremely slow vote-counting process, which can stretch on for weeks or even longer. That sluggishness is largely the result of a series of policy changes over the years that were meant to drive up voter turnout but have had limited success in doing so. One of those changes gives every registered voter a mail-in ballot automatically, and those ballots can arrive at an election office as many as seven days after Election Day and still be counted — as long as the envelope carries an Election Day postmark.
Despite that generous extension, the main reason rejection numbers climbed was ballots that arrived too late, according to figures compiled by the secretary of state’s office. Voting experts believe the core issue is ballots being postmarked after Election Day, which makes them ineligible to count. Analysts suspect recent changes within the U.S. Postal Service may be affecting when postmarks are actually applied to mail.
State data shows that 148,241 mail ballots were rejected in the June election, representing a rejection rate of 1.73% of all mail ballots cast.
To put that in perspective, 108,982 mail ballots were rejected in the 2024 primary at a rate of 1.56%, and 105,818 were thrown out during the 2022 primary at a similar rate.
Lateness alone accounted for 93,479 of the rejected ballots in June — by far the single largest reason for disqualification. That figure is up from roughly 70,000 in the 2022 primary and about 76,000 in the 2024 primary, though both of those elections drew fewer voters than last June’s contest.
Kim Alexander, who serves as president of the nonpartisan California Voter Foundation, said the surge in late-related rejections is deeply concerning. She noted that in addition to postal service issues, the spike may also be linked to a last-minute rush of ballots in June, when many voters held off on making a decision in what was a wide-open and unpredictable governor’s race.
“Ballots rejected due to lateness are caused primarily to being postmarked too late to count, not because they arrived too late to count,” Alexander said in an email.
While rejection rates have gone up and down over the years, the growing number of ballots set aside for lateness compared to previous recent elections “does really demand the question why this is happening,” said Mindy Romero, director of the Center for Inclusive Democracy, a nonpartisan research organization.
Back in January, a group made up mostly of Democratic U.S. senators sent a letter to the U.S. Postal Service expressing alarm that mail-processing changes could affect postmark dates on mail-in ballots during an election year that will decide control of Congress.
Updated Postal Service policy indicates that postmarks may no longer reflect the first day the agency received a piece of mail, but instead the day it was processed at one of its sorting centers. Because of recent consolidations within the Postal Service, those centers are increasingly located farther from certain communities — which could delay postmarks even further.
On Thursday, two Wisconsin Democrats — U.S. Sen. Tammy Baldwin and Gov. Tony Evers — called on the Postal Service to address delays that caused hundreds of ballots to show up after Election Day in that state in April. Separately, in June, a federal judge blocked President Donald Trump’s executive order that had sought to establish a federal voter list and restrict who could receive a mail ballot.
Earlier this year, California election officials had already urged voters to mail their ballots as early as possible, warning that Postal Service changes could slow down mail delivery.
Within California, the highest mail ballot rejection rate in June — 3.52% — was recorded in Tulare County, located in the farming-heavy Central Valley. Alpine County, situated south of Lake Tahoe, and Merced County, also in the Central Valley, both followed with rejection rates of 3.36%.
Nearly 44,000 ballots were set aside because a voter’s signature did not match the signature on file with county officials. More than 8,300 additional ballots were rejected because no signature at all appeared on the return envelope.
In 743 instances, the voter had already voted through another method, so the mail ballot was voided. Other reasons for rejection included a missing ballot inside the return envelope or multiple ballots stuffed into a single envelope.
The state data did not separate rejected ballots by the voter’s party registration.
While states like Florida and Texas wrap up their vote counts quickly, California consistently trails behind the rest of the nation in finalizing results.
After June’s primary, President Donald Trump used California’s reputation as the slowest vote-counter in the country to revisit his longstanding criticism of the state’s election processes. The Trump administration’s Department of Justice also launched an investigation into Los Angeles County’s elections.
Despite the rejection numbers, there is no evidence of any widespread fraud or systemic problems with mail voting, which has grown in popularity among both Democrats and Republicans. A 2025 report from the Brookings Institution found that documented cases of mail voting fraud are extremely rare — approximately four cases for every 10 million mail ballots cast.
