Can You Send Certified Mail to a P.O. Box?


June 8, 2023

Did you know that around 200 million Certified Mail letters are sent by Americans every year? Visualizing 200 million isn’t easy. If you could open one mail per second, you’ll finish 200 million letters in over six years. This massive amount of Certified Mail letters has been sent by Americans yearly since 2016.

If you’re wondering what Certified Mail is, it’s a USPS (United States Postal Service) mail service that provides proof of delivery for senders. 

As you may notice, the title of this article includes a P.O. Box, or Post Office Box, which is an alternate address you can get from your local post office. You use a P.O. Box to receive packages at an alternative address instead of your home. Both these services provide unique benefits to the sender. 

So what will happen if you send USPS Certified Mail to a P.O. Box? USPS Certified Mail is a USPS service that requires proof of delivery and the recipient’s signature. Meanwhile, a P.O. Box, which is an alternate address, allows you to receive packages without disclosing the actual address of a recipient.

After reading this article, you’ll better understand how Certified Mail and P.O. Boxes work. Also, you’ll learn how to address a letter that needs to be sent to a P.O. Box. Finally, you’ll get a broader look at the different uses of Certified Mail and what other services it includes.

Suppose you want to send Certified Mail or set up a P.O. Box. In that case, you can visit a local post office and inquire about these services from the local postal workers. 

To find a local post office near you, visit This website provides contact information and the location of more than 31,330 post offices in the United States. This website can also be handy when sending mail to addresses in the country, including P.O. Boxes. 

How Certified Mail Works With P.O. Boxes

A mail carrier puts a delivery notification inside a P.O. Box once a Certified Mail letter arrives at the post office. The notice instructs the recipient to show the delivery slip to the window clerk before receiving the letter or package. Note that an addressee is not obligated to sign for a mailpiece regardless of where it was delivered. 

Sending Certified Mail to a P.O. Box

Sending letters to P.O. Boxes doesn’t require a unique process. You just send the letter like any other mail, but instead of a regular street address, you place the P.O. Box address instead. However, you must purchase Certified Mail labels from USPS or an authorized third-party vendor to send Certified Mail. 

When you buy these labels, you must attach them to the letter and take them to your local post office. You can then drop the mail in one of the boxes and have USPS personnel take care of your mail piece. In the case of USPS, it will provide the receipt and tracking or delivery information. 

Steps for Sending Certified Mail

Here’s how to add Certified Mail as an additional service when sending your letter. If you want to print postage for your certified mail online, here’s what you must do:

  1. While creating your mailpiece, select the Extra Services delivery option.
  2. In the security drop-down menu, choose Certified Mail.
  3. Complete USPS form 3800 online, or you can do so at the post office.
  4. Check the return receipt tick box if you want a return receipt with your service.
  5. Fill out USPS form 3811 online or at your post office.
  6. Tick the electronic return receipt check box to get an electronic receipt.
  7. Click “Save” to confirm all your details.
  8. The final step is to print the postage.

 If the proof of mailing sender’s receipt is unnecessary, attach USPS Form 3800 to your mail or package. If you requested a physical return receipt, attach USPS Form 3811, and hand it to your mail carrier or place it in a USPS Postal Receiving Box.

How to Address an Envelope to Be Sent to a P.O. Box

Addressing an envelope to a P.O. Box is similar to addressing any mail piece you regularly send. Put the recipient’s name and address on the first line. If you are writing to a company or organization, place the name of that entity directly below the recipient’s name. Next, write P.O. Box followed by the two- to five-digit numbers that denote the postal box’s location.

The U.S. Postal Service prefers that senders omit punctuations, as this simplifies the postal system’s filtering and scanning process. The last line of the delivery address must include the ZIP code, city, state, and country, if applicable.

Leave the return address in the upper left-hand corner of the envelope. A return address is necessary so that you can inform the recipient of who sent the mail piece and return it if undelivered.


P.O. BOX 34345

Why Should You Use Certified Mail?

Certified Mail provides senders with a mailing receipt and a delivery record. Through this service, customers can also get an electronic return receipt of the letter or mail delivered via email

Certified Mail is a convenient way to ensure that time-sensitive documents are delivered quickly and have proof of their mailing. While Certified Mail costs more than regular mail, it is worth the extra money for essential documents, where mistakes could cost even more.

Uses for Certified Mail

Certified Mail is often used to send important documents that must be accompanied by proof of delivery, such as legal documents and contracts. You can also use it to send letters with sentimental or monetary value, such as an inheritance.

What Certified Mail Options Should You Consider While Mailing to a P.O. Box?

Now that you know P.O. Boxes can receive Certified Mail, here are some options to consider when mailing and sending letters and packages through Certified Mail: 

  • Certified Mail Restricted Delivery: You can direct the carrier to hand over the mail specifically to an intended recipient
  • Certified Mail Adult Signature Required: You can direct the letter carrier or the post office to only release the item or package to a receiver that’s 21 years of age
  • Certified Mail Adult Signature Restricted Delivery: You can direct the letter carrier to release the item or delivery only to the intended recipient over 21 years old. 

What Is Certified Mail?

Certified Mail is a mail service offered by the U.S. Postal Service that provides proof of mailing. Electronic USPS Tracking tells the sender when the package was delivered or if a delivery attempt was made.

Return Receipt, an optional extra service, provides proof of delivery through a postcard signed by the recipient or an email with an electronic copy of the recipient’s signature.

Certified Mail Service Is a Numbered Service That

  • Provides the shipper with a return receipt or an electronic receipt via email.
  • Offers electronic proof of delivery for your records.
  • Keeps your records for a definite time. The post office maintains a delivery record of signed receipts for two years from the date of mailing.

The delivery record for certified mail is not automatically returned to the sender.

  • Requesting a signature proof when mailing an item is possible by purchasing the Return Receipt Service. Customers can choose whether to receive the return receipt by mail or electronically.
  • Certified Mail can qualify for refunds.

Can You Use All USPS Mailing Classes with the Certified Mail Option?

No, you cannot. As mentioned above, there are limited mailing options you can choose from when shipping via Certified Mail.

Certified Mail Cost

You can purchase Certified Mail, which costs around $4.15, from the post office.

Tracking Certified Mail

You can check the delivery status in three ways:

  • Entering your tracking number on the USPS website.
  • Calling USPS to provide the tracking number for your letter’s status.
  • Checking bulk electronic file transfer, which is available to mailers who provide an electronic manifest to USPS.

How Long Does Certified Mail Take to Deliver?

The duration or time of mailing for your Certified Mail will depend on your shipping service. For example, if you opt for First-Class Mail, it will take one to five business days. For Priority Mail, delivery is usually made in one to three days. However, the postal service does not guarantee First-Class or Priority Mail delivery times.

What Mail Items Are Restricted or Prohibited to Send via Certified Mail?

Here are the items ineligible to be sent via Certified Mail:

  • Media Mail
  • International Mail
  • Priority Mail Express
  • Bound Printed Matter
  • USPS Retail Ground
  • Library Mail

Second Notice for Unclaimed Certified Mail

The second notice is usually the final notice for certified mail. It is sent within five days after receipt of the first notice. The total number of days it is held in the post office after its initial delivery attempt is 15 days.

When You’re Due a Refund on Certified Mail

You can apply for a refund of your certified mailing fee, excluding postage, if you have not received the mailing receipt and electronic verification within 30 days, even if you know your certified mail has been delivered. You can request a refund by doing the following:

  • Going online and visiting the refunds section at 
  • Visiting the nearest post office, submitting P.S. Form 3533, and providing proof of mailing and postage.

Refunds are granted at the discretion of postal service officials. The U.S. Postal Service does not refund the cost of Certified Mail if your letter cannot be delivered but a delivery attempt was made.

Certified vs. Registered Mail

Certified Mail offers the sender proof that a shipment has been mailed and delivered. In contrast, Registered Mail provides an automated system that allows the sender to track a package’s progress at any time.

You can use the Registered Mail service for extra protection when sending an important or valuable item. Certified Mail can send time-sensitive communications, such as tax returns and bank statements, from debtors or creditors.

Certified Mail vs. Delivery Confirmation

Certified Mail is a proof of mail delivery service. It is usually an added feature with a $4.15 fee to shipping options such as First-Class and Priority Mail. In contrast, Delivery Confirmation is free for First-Class, Priority, and Parcel Select items.

Frequently Asked Questions (FAQs)

  1. Can I send Certified Mail letters to a military APO or FPO address?

Yes, Certified Mail is eligible to deliver to APO (Army and Air Force Post Office), FPO (Fleet Post Office), or DPO (Diplomatic Post Office) locations.

  1. Can I ship Certified Mail letters to international places like Canada?

No, Certified Mail is not available for international mail shipping. Therefore, it is not available in Canada.

  1. Do I have to be at a post office to send certified mail?

No. You can simply hand the certified mail to your letter or mail carrier or place it in a USPS Postal Office Box.

  1. Does anyone at the recipient’s address have permission to sign for certified mail?

When certified mail arrives, anyone at the mailing address can sign for it. Suppose a mailing is marked as restricted certified mail. In that case, only the person it is addressed to or an authorized agent may sign for it upon delivery.

  1. On the receipt, should I put my name or the recipients?

Write the recipient’s name on the white and green “Certified Mail Receipt.” The recipient’s address should be at the bottom.

  1. If the certified mail is returned to the sender as not deliverable, should the sender sign the green card?

No, the sender should not sign the green card. The return of the envelope, with the green card still inside, shows that they attempted to send it.

  1. Can you send certified return receipt mail to a P.O. Box?

Yes, you can. When certified mail arrives at the delivery post office, the mail carrier will put a delivery notification inside the P.O. Box. The instructions will tell you to take the delivery slip to the mail clerk

Remember that a recipient has no legal obligation to sign for the mail, regardless of where it’s delivered.

  1. Can you get signature confirmation when sending certified mail through a P.O. Box?

Yes. As mentioned above, you can send certified mail to a P.O. Box. However, the recipient must show the delivery notification card that the post office will place inside the P.O. Box. This notification is what the recipient will get to notify them that they have certified mail for pick up from the post office window clerk and that proof of delivery is needed. 


  1. How to Prepare Certified Mail without our Certified Envelopes and Labels
  2. What else do I need to know about Certified Mail Services?
  3. What is Certified Mail? How to Send USPS Certified Letter
  4. What is Certified Mail?
  5. Insurance and Extra Services
  6. First-Class Mail
  7. Priority Mail
  8. USPS Certified Mail FAQ
  9. What are the Second and Final Notice and Return Dates for Redelivery?
  10. Is Certified Mail Eligible for a Refund?
  11. Registered Mail – The Basics
  12. USPS Delivery Confirmation