It is typically delivered within one to three business days. Priority Mail is available for packages and letters weighing more than 13 ounces. Priority is given to USPS first-class service over basic mail, and local mail is normally delivered in 2-3 days. First-class mail should arrive in roughly 4 days across the country. Standard mail can take up to 6 weeks to be delivered to some remote places. The postal service uses a complex system of sorting facilities to process the millions of pieces of mail every day. When your letter or package is mailed, it is given a serial number. This number tells us where to send it based on the destination address. As it travels through the mail, it will pass through many stations until it gets to its final destination. Mail sent from one US city to another will go through several stops before it gets to its final destination. It starts with local delivery, which covers most of the items we send through the mail. These include bills, catalogs, and newspapers. They are delivered to homes, businesses, and agencies that have signed up for this service. Items not picked up after 30 days are thrown out. Next comes regional delivery, which covers most large cities. These include letters, postcards, and small parcels. They are delivered to processing centers called post offices. Here, employees will scan the item's tracking number into a computer system to see where it has been and where it is going next.