You mail your federal tax return to different IRS addresses depending on your state of residence and whether you are enclosing a payment with your return. The IRS provides specific mailing addresses for Form 1040 and related forms, which vary by state and payment status. Here are the key points:

• If you are filing a paper federal tax return (Form 1040, 1040-SR, etc.), you must send it to the IRS address designated for your state.
• The mailing address differs if you are including a payment versus if you are not including a payment (for example, if you expect a refund).
• The IRS website has a detailed list of mailing addresses by state and form type for the 2025 tax year.
• If you live outside the U.S. or in a U.S. possession, there are separate mailing addresses for international filers.
• You can also use certain IRS-designated private delivery services (like FedEx or UPS) that have different addresses than USPS mail.
• To ensure your return is considered timely filed, it must be postmarked by the deadline, and using Certified Mail or a private delivery service can provide proof of mailing.

For exact mailing addresses, you should check the IRS official page "Where to File Paper Tax Returns With or Without a Payment," which lists addresses by state and form type

. The U.S. Postal Service also recommends verifying the correct IRS address on the IRS website before mailing

. In summary, you mail your federal tax return to the IRS address specific to your state and filing situation, which you can find on the IRS website or through official IRS resources.