Priority Mail Express is the fastest shipping method offered by the U.S. Postal Service, and it delivers packages overnight to most addresses inside the United States. In some cases, Express may take an additional day to deliver if the distance is particularly great between sender and recipient.
Priority Mail Express also offers service 365 days a year. Unlike traditional mail, which is only delivered on weekdays and Saturday, Express packages may be deliverable on Sundays, depending on the location. This service may incur an additional fee, but it can guarantee receipt even on holidays.
In most cases, Express parcels are delivered by 10:30 a.m. local time.