List of US Post Office Stores in Seneca, SC Outlet Note Regular Brands US Post Office South Carolina Seneca Rating 4.5 based on 76 votes Official Website https://www.usps.com/ Products Postal Service NameAddressPhone Name/Address/Phone US Post Office outlet - Seneca 283 Market St (864) 885-0872 US Post Office outlet - Seneca 508 E Main St (864) 882-8422 US Post Office outlet - Seneca 304 Richland Rd (864) 882-3999 People Also Viewed