What is the return mailing address of the IRS for form 2159?

The below information comes from page 6 of the instructions for the FORM 2159. Go to the IRS gov website and use the search box for FORM 2159

After you complete, sign (along with your spouse if this is a joint liability), and date

this agreement form, give it to your participating employer. If you received the

form by mail, please give the employer a copy of the letter that came with it.

Your employer should mark the payment frequency on the form and sign it. Then

the employer should return all parts of the form to the IRS address on your letter

or the address shown in the "For assistance" box on the front of the form.

If you need assistance, please call the appropriate telephone number below or

write IRS at the address shown on the form. However, if you received this

agreement by mail, please call the telephone number on the letter that came with

it or write IRS at the address shown on the letter.

For assistance, call: 1-800-829-0115 (Business),or

1-800-829-8374 (Individual -- Self-Employed/Business Owners), or

1-800-829-0922 (Individuals -- Wage Earners)