The mailing instructions for Form 940 are available on the IRS website. The mailing address depends on the home state of the filing employer and on whether or not payment is mailed with the form.
On the IRS website, type "940 where do you file" in the search box. From the Search Results page, click on the link for Instructions for Form 940. On the page that opens, click on Where Do You File? to find a table of all mailing addresses for Form 940. The IRS uses Form 940 to determine the amount of Federal Unemployment Tax that an employer has to pay. Under the Federal Unemployment Tax Act, the collected taxes are used to pay out compensation to unemployed workers.