More than 20,000 Washington ballots went uncounted in the August primary because they arrived with late postmarks.

That is 32% more than in 2024, even though fewer people voted this year. The spike hit rural counties hardest, a pattern that state officials say underscores the importance of drop boxes ahead of the Nov. 3 general election.

King County bucked the trend. Late-ballot rejections fell 20.2% compared with 2024, according to an analysis released by U.S. Sen. Maria Cantwell's office.

The county had already added drop boxes before the primary and used voter-registration data to place them in neighborhoods with high registration but low turnout, King County ballot collection and logistics supervisor Steve Barron said in July.

Nearly 70% of Washington voters returned their ballots through drop boxes in August, up from 2024, the Washington State Standard reported.

The problem traces to a U.S. Postal Service rule finalized in December 2025. Under the policy, ballots are postmarked at regional processing centers rather than local post offices. If a post office sits more than 50 miles from a center, mail is transported there once a day instead of twice.

A Snohomish County test during a February 2026 special election showed the real-world effect. Of 15 envelopes mailed before 9 a.m. on Election Day, only seven got a same-day postmark, KOMO News reported.

Seven were stamped the next day and would not have been counted. One had not arrived two days later.

In 19 counties, the rate of late-postmarked ballots more than doubled. Mason County saw a 329.7% increase.

Stevens County saw a 303.7% jump, with more than 600 ballots postmarked after the Aug. 4 election.

Stevens County Auditor Lori Larsen said the pattern does not match typical voter behavior. "Their postmarks were between Election Day on the 4th and when we received it on the seventh," Larsen told KIRO 7. "That doesn't look like voter behavior to me."

Larsen is working to double Stevens County's drop-box sites from five to ten before November.

Secretary of State Steve Hobbs said his office has spent $400,000 on voter education urging drop-box use and reimbursed counties $357,647 for new drop boxes and reprinted mailing envelopes.

Hobbs said he has discussed additional state funding for rural drop boxes with the Governor's office.

Washington's 5.1 million ballots are already printed, the Seattle Times reported. Most will be mailed to voters on Friday, Oct. 16.

The ballot includes three statewide initiatives, five state Supreme Court races, more than 100 legislative contests and every U.S. House seat.

In one Whatcom County legislative district, two Democratic state Senate candidates were separated by four votes in the primary.

That county rejected 615 ballots for lateness, 179 more than two years ago.

A federal court on Thursday, Aug. 27 temporarily blocked the USPS postmarking rule while a legal challenge by Washington and 24 other states moves forward. No ruling date has been set for the full case.

At a Wednesday, Sept. 2 news conference in Seattle, Hobbs urged voters to treat drop boxes as the default.

USPS acknowledged in a statement that its transportation changes may result in postmarks that do not match the date a ballot was mailed.

King County Elections lists drop-box locations on its website ahead of the Oct. 16 ballot mailing.