The United States Postal Service provides a ZIP code look up service on its website. Also, UnitedStatesZipCodes.org displays maps of all ZIP codes in the United States.
To find a specific ZIP code using the USPS lookup page, navigate to USPS.com and click on Look Up a ZIP Code. Enter the street address, city and state, and the ZIP code plus the four-digit extension is displayed. The site also provides a reverse lookup tool that lists all cities in a particular ZIP code.
To view ZIP code maps, navigate to UnitedStatesZipCodes.org and enter the physical address or the ZIP code to display a regional map showing ZIP code boundaries.