It isn't. USPS Domestic Mail Manual 602 1.4:
ZIP Codes are required on Express Mail, Presorted and automation price First-Class Mail, Periodicals mail, Standard Mail, Package Services mail (except single-piece price Parcel Post), all mail sent to military addresses within the United States and to APO and FPO addresses, all official mail (penalty mail), all business reply mail, and all merchandise return service mail.
nless required above, ZIP Codes may be omitted from single-piece price First-Class Mail (including Priority Mail), single-piece price Parcel Post, and pieces bearing a simplified address.
For a complete list of Jacksonville's zip-codes go to 555AK.com. Posting all of Jacksonville's zip-codes here on WikiAnswers is impossible, because Jacksonville is such a big city and has numerous zip codes.
Go to the Post Office web address. USPS.com. Zip codes are listed there.
Zip Codes are only used in the United States. There are no international zip codes.
Houston, Texas is a very large city, therefore there are around 178 zip codes. These zip codes go in numeric order from 77001-77299.
There a few places that you can go to get more information on the history of zip codes in the US. First and the I am sure you know this is Wikipedia. Also if you go to the USPS website there is a history of the postal service so you will probably get some information on zip codes there.
Numbers are used in zip codes.
There are 3 zip codes but I don't know which one you want. Go to the USPS site and click on Lookup Zip Codes (see Related Links).
Zip codes help someone to locate the correct location. This means that Delaware alone has many. Luckily, all the zip codes in one state tend to start with the first few letters. In Delaware, the codes go from 19701-19980.
go to www.50states.com/cityguides/ this should find any city zip there is!
There are all kinds of different companies that will allow someone to look up zip codes. Some of these companies are; YellowPages, Redelivery, and USPS. Another place that someone can go to look up zip codes is the local library, and/or the local post office.
27 zip codes
There are approximately 43000 zip codes. Number of ZIP codes periodically changes. For example, around 200 zip codes were added in the U.S. in 2006-2007.