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.
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 asking this question in the first place, then it’s time for a new accountant.