The Postal Service says it's delivered a record 122 million ballots ahead of the election.
That includes blank ballots mailed to voters and completed ballots.
This year has seen a historic rise in early voting, but many voters have been worried about problems at the Postal Service affecting mail-in ballots.
The USPS says it's been delivering all first-class mail in an average of two-and-a half-days.
It said in a statement it has initiated efforts to help the election run smoothly,such as extra pick-ups and deliveries.