Post Office - Spokane 904 W Riverside Ave Ste 109 Spokane, WA 99201 Phone : (509) 252-2337 Business Category Post Offices Toll-Free           (800) ASK-USPS Post Office - Riverside 904 W Riverside Ave Spokane, WA 99201 Phone : (509) 252-2337 Business Category Post Offices Toll-Free           (800) ASK-USPS Fax           (509) 838-6683