Post Office - Round Rock West 797 Sam Bass Rd Round Rock, TX 78681 Phone : (512) 238-9461 Business Category Post Offices Toll-Free           (800) ASK-USPS Fax           (512) 255-8764 Automated Postal Center - Round Rock West 797 Sam Bass Rd Round Rock, TX 78681 Phone : (512) 238-9461 Business Category Automated Postal Centers Toll-Free           (800) ASK-USPS Fax           (512) 255-8764