A person drops applications for mail-in ballots into a mailbox in Omaha, Neb. U.S. Postal Service records show delivery delays have persisted across the country as millions of Americans began voting by mail, raising the possibility of ballots being rejected because they arrive too late.

U.S. Postal Service records show delivery delays have persisted across the country as millions of Americans are voting by mail, raising the possibility of ballots being rejected because they arrive too late.

Postal data through Oct. 9, released through a federal court order, show nearly all the agency’s delivery regions missing its target of having at least 95% of first-class mail arrive within five days. Parts of the presidential battleground states of Minnesota, Wisconsin, Michigan, Pennsylvania and Ohio fell short of delivery goals by wide margins as the agency struggles to regain its footing after a tumultuous summer.

The districts that include the major urban areas and their suburbs in each of those states all performed below the national average for on-time delivery, with the area around Pittsburgh in western Pennsylvania the lone exception.

The delays are a worrisome sign for voters who still have not returned their absentee ballots. That is especially true in states such as Michigan, where ballots must be received by Election Day. Other states require a postmark by Nov. 3.

“We do encourage people who are worried about ballots not getting here on time to get them in as soon as possible,” said Perry County Commissioner Brenda Watson in Pennsylvania.

She said her office has sent out more than 600,000 absentee ballots, more than double the number from the primary, and has extended office hours so staff can monitor a drop box.