1120 / 1120s Mailing Address

Updated July 14, 2015
What is the 1120 / 1120s mailing address?
If the corporation’s principal business office, or agency is located in Illinois, and
Total assets at the end of the tax year are less than $10 million and Schedule M-3 is not filed, then use

Department of the Treasury
Internal Revenue Service
Cincinnati, OH 45999-0013

For other corporation addresses and IRS mailing locations please see the complete article in our main accounting articles section.
Mailing your return to the wrong IRS office can result in either an increased processing time for the return, or it being lost in the system. If it is lost, you will probably end up paying additional penalties and interest.
If you are having problems with your 1120 / 1120s Mailing Address or have issues with your accounting in general, we would love to help. I enjoy hearing from my readers, and can be contacted at
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Chris Amundson is the President of Accounting Solutions Ltd., a full service public accounting firm of Certified Public Accountants and Enrolled Agents handling the bookkeeping, accounting, tax preparation, and audit representation needs of Businesses, Estates, Trusts, and Upper Income Individuals.