A directory of U.S. postal codes is available at UnitedStatesZIPCodes.org or through the ZIP code finder at Tools.USPS.com. UnitedStatesZIPCodes.org features full ZIP code directories by state or a search by address, city or county. Tools.USPS.com allows searches of ZIP code directories by city and state or street address.
UnitedStatesZIPCodes.org features four different ZIP code types including standard, PO Box, military and unique. USPS designated unique ZIP codes for single, large volume mailing addresses, such as the special ZIP code used by the CIA. UnitedStatesZIPCodes.org also offers a map with general ZIP code regions and boundary lines, as of 2015. The site also features data for each ZIP code including population, land area, water area, housing units and other information.