These
sites are maintained by the USPS and are included here for your convenience.
Carrier
Route Lookups – choose “Search by Address”, then type
in your address and click enter. On the
next page you will see a link allowing you to view “Mailing Industry
Information.” Here you will see the
carrier route that corresponds to the address you typed in.
http://www.usps.com/zip4/welcome.htm?from=global&page=2132findzip
USPS
Web-based services
City/ZIP
Lookup – find all of the ZIP Codes in a city
http://zip4.usps.com/zip4/citytown.jsp