What is the address to mail in federal income tax?

The address to mail your federal income tax return depends on your location and whether you're enclosing a payment. For most taxpayers, the return should be sent to the appropriate IRS processing center based on your state, which can be found on the IRS website. If you're including a payment, the address may differ; again, refer to the IRS guidelines for your specific situation. Always check the latest information on the IRS website for the most accurate mailing addresses.