If you’ve forgotten your PO Box number, the quickest way to find it is to look at the key: PO Box keys are stamped with the box number they open. If the key isn’t handy, your USPS.com account, your rental paperwork, and old email confirmations from USPS all show the number, and the post office where the box is located can look it up for you with ID.
Look at the Key
Flip the key over. PO Box keys are engraved or stamped with the box number, usually a short set of digits etched into the metal. Most people miss this because they assume the number only lives on paperwork. It takes about five seconds and solves the problem outright when the key is nearby.
Check Your Records and Email
No key? Work the paper trail. Your original rental agreement, any renewal receipts, and your copy of PS Form 1093 (the USPS PO Box application) all list the full box address. Check the filing cabinet, the junk drawer, wherever postal receipts end up.
Digital records are usually faster because you can search them. In your email, look for USPS confirmations from around the time you opened or renewed the box. Payment confirmations and renewal reminders both include the box number. Bank and credit card statements are another angle: USPS transaction descriptions sometimes show the box number, and at minimum they show the ZIP code of the post office, which helps if you rent boxes at more than one location.
Log In to Your USPS.com Account
If you set up a USPS.com account when you rented the box, the number is already sitting in that account. Log in at usps.com and open “Manage PO Box.” The dashboard shows your active box number along with payment history and renewal dates.1USPS. PO Boxes
If you never created an online account, you can link an existing box to a new profile from the same page by selecting “Link” and entering your PO Box number, ZIP code, and last name or business name exactly as they appear on the reservation.2USPS. PO Boxes Online Key Steps – Linking a PO Box Online The obvious limitation: linking requires the box number, so it doesn’t rescue you if the number is what you’ve lost. Once you recover it another way, linking the box now prevents this problem the next time.
Informed Delivery as a Backup
If you’re already enrolled in USPS Informed Delivery, your dashboard shows grayscale scans of incoming letter-sized mail, and each scan displays the address side of the envelope. Your PO Box number appears on every piece addressed to you. Informed Delivery is available for PO Box addresses in eligible ZIP codes, and PO Box holders enroll through a USPS.com business account.3USPS. Informed Delivery – Mail and Package Notifications
Ask the Post Office
When nothing else works, go to the post office where your box is located. Detailed box records are held locally, and a clerk can pull your rental file, including the PS Form 1093 you filled out when you applied, and confirm the box number after checking your ID. This is the most reliable route.
If a visit isn’t practical, call USPS customer service at 1-800-275-8777, staffed Monday through Friday, 8 AM to 8:30 PM Eastern, and Saturday, 8 AM to 6 PM Eastern.4USPS. Contact Us Expect the general line to route you to your specific branch, since that’s where the records live.
ID You’ll Need
For any in-person PO Box business, USPS requires two current forms of ID traceable to you: one photo ID and one non-photo ID.5USPS. PO Box Help
Photo IDs the post office accepts:
- Driver’s license or state ID card
- Passport or alien registration card
- Military or government ID
- University or recognized corporate ID
Non-photo IDs the post office accepts:
- Current lease, mortgage, or deed of trust
- Voter or vehicle registration card
- Home or vehicle insurance policy
Social Security cards, credit cards, and birth certificates are not accepted in either category, and a second photo ID does not substitute for the required non-photo ID.6USPS. Acceptable Forms of Identification
Check That Your Box Is Still Active
If the reason you lost track of the number is that you’ve been away or out of touch for a while, confirm the rental is still current before you count on the box. PO Box rent is due every six or twelve months, and USPS sends email reminders when payment is due. Miss the due date and you get a 10-day grace period before the post office closes the box.7About USPS. Policies, Procedures, and Forms Updates
Once a box is closed for nonpayment, incoming mail is returned to the sender, and you may be assigned a different number when you reopen service, which means updating your address everywhere. A $27 late payment fee applies on top of the back rent.8Postal Explorer. Domestic – PO Box Service Once you have the number back, linking the box to your USPS.com account and turning on automatic payments keeps you from repeating any of this.1USPS. PO Boxes