PlainZIP places U.S. ZIP codes and states their figures from public data: the Census Bureau, FHFA and the IRS, with town and neighborhood names from GeoNames and simplemaps (both CC BY 4.0; PlainZIP joins them to Census areas). It is not affiliated with the United States Postal Service or any government agency. ZIP Code™ and ZIP+4® are trademarks of the United States Postal Service. © 2026 PlainZIP. Look up a street address's ZIP+4 with the USPS ZIP Code Lookup.