Why do the mailing instructions for Form 940 vary by state?

The mailing instructions for IRS Form 940 are different by state because the address that's used to send the form depends entirely on where the employer is located and whether a payment is included with the return, Patriot Software explains. All address are listed on the IRS website.

If there is no payment included with the form, the form is mailed to IRS office in Ogden, Utah, or Cincinnati, Ohio, according to the IRS. If the employer is making a payment, the forms are mailed to an IRS office in Hartford, Connecticut, or Cincinnati, Ohio.

Form 940 is used to report unemployment tax that must be paid for eligible employees, but the form must be filed whether or not the tax is due, the IRS notes.