What is the address in Washington to mail IRS form 1099-misc?

To mail IRS Form 1099-MISC, send it to the appropriate address based on your state. For most states, including Washington, the address is: Department of the Treasury, Internal Revenue Service, Austin, TX 73301-0215. However, if you're filing with a payment, use the address: Internal Revenue Service, P.O. Box 37008, Hartford, CT 06176-0008. Always double-check the latest IRS guidelines for any updates.