Where do I mail business tax returns to the IRS?

There is no single address. The IRS routes business returns to different service centers based on the form and your state. Some forms also split by total assets, and others by whether you enclose a payment. Confirm the current address on the IRS Where to File page for your specific form before mailing.

Where do I mail Form 1120-S?

The address depends on where the corporation's principal business is located. The Kansas City list covers 23 states plus DC. A corporation on that list mails to Kansas City, MO 64999-0013 when its total assets are under $10 million and it does not file Schedule M-3. In every other case it mails to Ogden, UT 84201-0013, and so do corporations in the other 27 states. A corporation in a foreign country or U.S. possession uses P.O. Box 409101, Ogden, UT 84409.

Is the mailing address the same for Form 1120 and Form 1065?

Not exactly. On the IRS pages we checked on October 14, 2026, Form 1120, 1120-S, and 1065 use the same Kansas City and Ogden service centers and the same state groups. The ZIP+4 codes differ: 0012 for Form 1120, 0013 for Form 1120-S, and 0011 for Form 1065. Copy the address from the page for the exact form you file.

How do I update my business address with the IRS?

File Form 8822-B. The IRS says businesses use it to report a new business mailing address, a new business location, or a new responsible party. A change of responsible party must be reported within 60 days. Our Form 8822-B guide walks through the form box by box.

Can I use a PO Box as the address on my business tax return?

The address on your return is where the IRS mails notices and correspondence back, so it should be a real, deliverable street address. A box number that cannot receive a full range of mail is a weak choice, because a returned IRS notice can turn into a missed deadline. You can confirm an address is deliverable before you use it.

Where to Mail Form 1120-S: The IRS Kansas City or Ogden Address for Your State

Short answer

A corporation located in a US state or the District of Columbia mails Form 1120-S to Kansas City, MO 64999-0013 or Ogden, UT 84201-0013. The state, total assets, and Schedule M-3 decide which one. A corporation in a foreign country or U.S. possession uses P.O. Box 409101, Ogden, UT 84409.

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Key takeaways

A corporation located in a US state or the District of Columbia mails Form 1120-S to Kansas City, MO 64999-0013 or Ogden, UT 84201-0013, depending on the state, total assets, and Schedule M-3. A corporation in a foreign country or U.S. possession uses P.O. Box 409101, Ogden, UT 84409.
In the state rows of the IRS pages, Form 1120, 1120-S, and 1065 share the same two cities but use different ZIP+4 codes. Copy the address from the IRS page for the exact form you file.
An S corporation can be required to e-file instead of mailing, because the e-file rule applies when a corporation files 10 or more returns of any type in a calendar year.
Every mailed form works best with a real, deliverable US street address the IRS can send its response back to, which is where a business address you actually receive mail at matters.

Before you start

Know which form you are filing, since Form 1120, 1120-S, 1065, and 941 each have their own mailing instructions.
Have the current IRS Where to File page open, because service center addresses change and depend on your state.
For Form 1120-S, know your total assets at the end of the tax year (page 1, item F) and whether you file Schedule M-3.

Who this is for

Corporation and S-corp owners mailing Form 1120 or 1120-S.
LLC and partnership owners who file by paper rather than e-file.
Anyone who wants IRS mail and notices to reach a real business address.

For Form 1120-S, a corporation located in a US state or the District of Columbia mails to Kansas City, MO 64999-0013 or Ogden, UT 84201-0013, based on its state, total assets, and Schedule M-3. A corporation in a foreign country or U.S. possession uses P.O. Box 409101, Ogden, UT 84409.

This guide covers how that routing works and where corporate forms like 1120 and 1120-S go. The guide also covers where to find the address for partnership and payroll forms, and why the address the IRS mails back to matters as much as the one you send to.

Did this answer your question?

Quick Answer: There Is No Single IRS Address

Each business tax form has its own mailing instructions. Within one form, the address can change with your state. Some forms also split by total assets, and others split by whether a payment is enclosed. Start from the form you file and then find your row.

Form	Who files it	How to find the address
Form 1120 / 1120-S	C-corporations and S-corporations	Kansas City or Ogden, by state, total assets, and Schedule M-3 (full Form 1120-S table below)
Form 1065	Partnerships and multi-member LLCs	See the dedicated routing guide and current 1065 instructions
Form 941	Employers filing payroll tax	See the dedicated payroll guide and current 941 instructions
Estimated payments (1040-ES)	Owners paying estimated tax personally	See the quarterly estimated tax guide

Routing starts from the form. The exact service center depends on your state and, for some forms, on total assets or on whether a payment is enclosed.

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Form 1120-S Mailing Address: Where to Send an S Corporation Return

The IRS page Where to file your taxes for Form 1120-S has four rows and three different addresses. The table below copies that page as we read it on October 14, 2026. The page shows a last-reviewed date of August 27, 2026.

If the corporation's principal business, office, or agency is located in:	And the total assets at the end of the tax year are:	Use the following IRS center address:
Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia, West Virginia, Wisconsin	Less than $10 million and Schedule M-3 is not filed	Department of the Treasury, Internal Revenue Service, Kansas City, MO 64999-0013
(Any of the above)	$10 million or more or Schedule M-3 is filed	Department of the Treasury, Internal Revenue Service, Ogden, UT 84201-0013
Alabama, Alaska, Arizona, Arkansas, California, Colorado, Florida, Hawaii, Idaho, Iowa, Kansas, Louisiana, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, Wyoming	Any amount	Department of the Treasury, Internal Revenue Service, Ogden, UT 84201-0013
A foreign country or U.S. possession	Any amount	Internal Revenue Service, P.O. Box 409101, Ogden, UT 84409

Source: IRS, Where to file your taxes for Form 1120-S, read October 14, 2026. Address line breaks on the IRS page are shown here as commas.

We counted the two state lists on the IRS page. The Kansas City group has 24 entries: 23 states plus the District of Columbia. The Ogden group has 27 states.

A corporation in the Kansas City group still mails to Ogden in two cases. The first case is total assets of $10 million or more at the end of the tax year. The second case is filing Schedule M-3. One of the two is enough.

The total assets figure is the one on Form 1120-S, page 1, item F, according to the 2025 Instructions for Form 1120-S. Those instructions print the same three addresses. The instructions say “U.S. territory” where the web page says “U.S. possession.”

An S corporation that reaches the e-file threshold generally files the return electronically instead of mailing it. For returns filed on or after January 1, 2024, the instructions say S corporations “are required to e-file Form 1120-S if they file 10 or more returns of any type during the calendar year.” That count includes income tax, employment tax, excise tax, and information returns. A corporation can ask the IRS for a waiver if e-filing would cause a hardship.

Private delivery services cannot deliver to an IRS P.O. box, so the foreign row needs the U.S. Postal Service. If you use a designated private delivery service for the other rows, use the street addresses on the IRS private delivery service address page.

Form 1120 and Form 1065: Same Cities, Different ZIP Codes

The Form 1120 page uses the same two state groups and the same total assets test. The cities are the same, but the ZIP+4 codes end in 0012: Kansas City, MO 64999-0012 and Ogden, UT 84201-0012. The Form 1065 page for partnerships uses codes that end in 0011.

We compared the three IRS pages side by side on October 14, 2026. In the state rows, the cities and the state lists matched. The last four digits of the ZIP+4 code were different on each page. The IRS updates these pages from time to time, so check the page for your exact form each filing season instead of reusing last year's address.

Form 1065 and Payroll Forms: Use the Dedicated Guides

Partnership and payroll forms have their own routing, and we cover each in detail elsewhere so this guide can stay focused on the overall picture.

For partnerships and multi-member LLCs, our guide on the Form 1065 and K-1 mailing address covers the service center routing.
For payroll and quarterly filings, the quarterly estimated tax mailing address guide covers Form 941 and 1040-ES.

With a Payment vs Without a Payment

Some forms have two addresses: one for a return with a payment and one for a return without a payment. Form 941 is an example. Its IRS page sends a return without a payment to Kansas City or Ogden and a return with a payment to a P.O. box in Louisville, KY.

The IRS pages for Form 1120, 1120-S, and 1065 have no payment column. Those pages split by state, total assets, and Schedule M-3 instead. Separately, the 1120-S instructions say corporations “must use electronic funds transfers (EFT) to make all federal tax deposits.” If your form does have a payment column, match the address to whether a check is in the envelope.

Why a Street Address Beats a PO Box for IRS Mail

The address you put on the form as your business address is the one the IRS uses to mail back notices, refunds, and correspondence. That address works best as a real, deliverable street address, since the IRS instructions only fall back to a box number when the post office does not deliver to your street address, and a returned notice can turn into a missed deadline.

The 1120-S instructions ask for the address of the corporation's principal office or place of business. If an accountant or another third party receives the corporation's mail, the instructions say to write “C/O” on the street address line, followed by that party's name and address. The same instructions say not to use the address of the registered agent in the state of incorporation.

Receiving the IRS Response at a Business Address

Filing is only half of it. The IRS replies by mail, and those letters are time-sensitive, so the address on your return needs to be one where mail is received and handled rather than left in a box you rarely check.

A US business address that receives your mail and forwards it gives IRS letters a place to arrive. We run our Silicon Valley location ourselves, and the Silicon Valley page explains how it works. Our business addresses in Los Angeles are on the Los Angeles page.

Check the Address Is Deliverable First

Before you put an address on a business tax form, it is worth confirming it is a real, deliverable street address rather than something that will bounce an IRS notice.

You can confirm how an address is classified and whether it is deliverable with our free Address Checker before you use it on a return.

Keep One Address Across Your Forms

Your business address shows up on more than one form, and the forms work best when they match. If the address changes, tell the IRS on Form 8822-B. The IRS says the form reports a change to the business mailing address, the business location, or the responsible party. Our Form 8822-B guide walks through it box by box, and our guide on changing an LLC business address covers the wider move.

If you are weighing whether a non-home business address is accepted on IRS forms at all, our guide on whether the IRS accepts a virtual address walks through it.

There is no single IRS address for business taxes. For Form 1120-S, the service center is Kansas City or Ogden, based on your state, your total assets, and Schedule M-3. For any form, start from the current IRS Where to File page instead of reusing an old address.

Put a real, deliverable business address on the return so the IRS can write back, confirm it is deliverable first, and keep the same address across your forms, and the mailing step stops being the part that delays your filing.