Post Office - Parker 301 2nd Ave Parker, WA 98939 Phone : (509) 877-3150 Post Office - Parker Business Category Post Offices Toll-Free           (800) ASK-USPS United States Government--nuclear Regulatory Commission, Parker 401 W 2nd St Wapato, WA 98951 Phone : (509) 877-3150 United States Government--nuclear Regulatory Commission, Parker Business Category Government Offices-Federal Government Offices & Public Schools