Where to mail a IRS extension?

To mail an IRS extension request (Form 4868), you should send it to the address specified for your location on the form. Generally, if you are filing from within the United States, it goes to the address listed for your state. If you're sending it from outside the U.S., you'll use a different address provided in the instructions. Make sure to check the latest IRS guidelines to confirm the correct mailing address based on your circumstances.