Certified Mail tracking gives you a view of a letter’s progress through USPS. For deadline-sensitive notices, though, the tracking number is only part of the record. You also need to know what each scan means, which event documents acceptance, and how you will retrieve the mailing history later.
What the 9407 tracking number identifies
Each Certified Mail piece gets its own tracking number, commonly beginning with 9407. The number is tied to the barcode on the Certified Mail label or envelope. USPS uses it to connect the piece to its tracking events.
You can find the number on the mailpiece and on the mailing receipt. Enter it in USPS Tracking to see the events USPS has recorded.
A number alone does not prove that USPS has the letter. A label can be created before the piece is handed over. Look for an acceptance event to confirm that USPS has recorded possession.
What the USPS tracking events mean
USPS events describe what has been scanned or recorded. Some terms vary slightly by mailpiece or tracking view. The USPS tracking status guide explains the main statuses.
| Tracking event | What it means |
|---|---|
| Accepted or USPS in possession of item | USPS has received the mailpiece. This is the key event documenting the acceptance date. |
| In transit, arrived at facility, or departed facility | USPS is processing or transporting the piece through its network. These events may appear more than once, including at the same facility. |
| Arrived at post office | The piece has reached the local delivery unit and is being prepared for delivery. |
| Out for delivery | The piece has been prepared for delivery that day. It may arrive at a different time than the recipient’s regular mail. |
| Delivered | USPS recorded a delivery date, time, and location. This confirms a delivery event, but does not necessarily include a recipient signature. |
| Notice left or attempted delivery | USPS recorded an attempt, but an authorized recipient was unavailable or the carrier could not leave the piece securely. The recipient may need to arrange redelivery or pick it up. |
| Awaiting item or no scan yet | USPS may have label information but no recorded possession event. The piece may not have been handed to USPS yet, or its first scan may not have posted. |
A related status, Shipment Received, Package Acceptance Pending, can mean USPS has received a container or pallet but has not yet scanned each individual piece. Check again for the individual acceptance event.
Why the acceptance scan matters for deadlines
When your deadline depends on when USPS took possession, focus on the acceptance record. It documents the date USPS accepted the piece and can support a compliance window when the governing rule counts from mailing or acceptance.
A drop into a collection box does not produce an individual acceptance scan at handoff. If the date matters, hand the mailpiece to a carrier and confirm it is scanned, or use a mailing service that hands it to USPS and retains the acceptance record.
The acceptance date is not always the same as a postmark date. A machine-applied postmark can reflect a later processing event. See our guide to the 2026 postmark rule and the difference between a postmark and postal acceptance. The mailing method and the rule that applies to your notice both matter.
For a practical overview of preparing and handing off mail, see our 2026 desk-mailing guide.
A tracking lookup is not a long-term record
A USPS tracking lookup is useful while the information remains available online. It is not the same as keeping a complete mailing record that you can retrieve years later.
USPS currently says online tracking access is generally limited to 120 days for non-signature items and two years for signature items. Eligible records may have longer access through USPS Tracking Plus, subject to USPS terms and options.
For a later dispute or audit, you may need more than a status page. You may need to connect the original mailing to its acceptance event, tracking history, delivery confirmation, and signature record.
Certified Mail Envelopes keeps USPS acceptance, tracking history, delivery confirmation, and signature records together in a searchable archive for 10+ years. That means your team can search for a mailing and retrieve its record set without relying on an old browser lookup or a paper receipt filed elsewhere.
How tracking works for dozens or hundreds of pieces
For a single letter, looking up one tracking number may be enough. For a batch, your process needs to connect each number to the right recipient.
Every recipient gets an individual Certified Mail tracking number. Keep that number tied to the recipient’s address and, where appropriate, the document or case reference. That mapping lets you confirm which piece has an acceptance scan, which is still moving, and which has a delivery or attempt event.
Teams can prepare mailing data through Excel, CSV, API, or secure SFTP workflows. At higher volumes, a list of numbers to check one by one can become hard to maintain. A searchable, address-linked record set makes it easier to review a campaign and find a specific mailing when someone asks.
If your mailing includes sensitive documents or recipient details, see our guide to mailing-data security.
What to do when tracking stops moving
A gap between scans does not always mean something has gone wrong. The piece may be moving between facilities without a new visible event yet. Start by checking the tracking number and the most recent event on USPS Tracking.
Then use the status to choose a next step:
- Awaiting item: Check whether the piece has been handed to USPS. If it has, contact the person or service that sent it and confirm the handoff and acceptance record.
- No movement after acceptance: Keep the tracking history and receipt. If the piece is past its expected delivery date or remains stalled, use USPS’s delayed-mail guidance or submit a service request through USPS.
- Out for delivery, but no delivery event: USPS advises contacting the local Post Office through a service request if a full postal business day passes after the out-for-delivery scan without delivery.
- Notice left or attempted delivery: Check the tracking details and any notice at the address. The recipient may be able to schedule redelivery or pick up the piece. Keep the attempt event with the mailing record. It documents what USPS recorded, even though it is not confirmation of completed delivery.
When you contact USPS, have the tracking number and acceptance receipt ready. Keep any follow-up or service-request details with the same record.
What Return Receipt adds
Delivery confirmation tells you USPS recorded delivery. If you also need a signature record, request Certified Mail with Return Receipt.
A Return Receipt adds evidence such as the delivery date, the person to whom the piece was delivered, and the delivery address when it differs. You can choose a paper Return Receipt, often called the green card, or an electronic Return Receipt when available for the mailing.
The paper card is returned by mail. The electronic option provides a USPS proof-of-delivery letter with the signature image, generally as a PDF. USPS requires the electronic option to be requested at mailing; its electronic Return Receipt records are retained for two years. USPS describes the electronic document as designed to be equivalent to the paper receipt, while legal admissibility is determined by the relevant court.
Neither option is automatic. Choose the service that matches the record you need, and keep it with the tracking history and acceptance evidence. Review USPS current rates and extra-service details before mailing.
Keep your tracking records ready for review
Before closing out a mailing, check that you can retrieve:
- The final document and recipient address.
- The Certified Mail tracking number for that recipient.
- The USPS acceptance event and its date.
- The complete tracking history, including delivery or attempted delivery.
- The signature record, if you requested Return Receipt.
- Any USPS service request or follow-up notes.
- A searchable copy of the record set for your retention period.
Certified Mail tracking shows the path USPS recorded. Acceptance documents when USPS took possession. A retained record set lets you put both facts in context when you need them later.
You can review Certified Mail service options for desk-based labels or full-service mailings. For full-service mailings submitted before 5 PM ET, we print, stuff, apply postage, and mail the pieces the same business day, with USPS records kept together in your searchable archive.