Where do I file my annual return? Mail your return to the address provided in the instructions. For most organizations, the filing address is Department of the Treasury, Internal Revenue Service Center, Ogden, UT 84201-0027. If your organization's principal business, office, or agency is located in a foreign country or a U.S. possession, send the return to the Internal Revenue Service Center, P.O. Box 409101, Ogden, UT 84409. Annual returns may also be filed electronically - a quick, secure, and more accurate method than filing paper returns. For more information, see e-file for Charities and Non-Profits.