According to the US Postal Service: http://uspostalservice.marketingsyndrome.com/zip-code.html
ZIP stands for Zoning Improvement Plan which began on July 1, 1963 as a solution to the explosive growth of business mail. The Post Office didn't require anyone to use the new ZIP Code system at the beginning, but in 1967, the Post Office required mailers of second-class and third-class mail to presort by ZIP Code
.
From a North Platte Public Library Librarian
There are thousands of Zip Codes assigned to Virginia. Visit the USPS web site to find the Zip Code for the specific city and address you need.
Personally, I would go with a text field. It will allow for non US postal codes like those used in Canada.
19114 is one of almost 100 zip codes assigned to the city of Philadelphia. They all start with the digits 191 followed by two additional digits.
Zip codes are assigned by location in a state and county. There might be many Sun Valley Drives in the U.S., and each would have a different zip code.
You will need to provide a specific address, as ZIP+4 codes are typically assigned to blocks, individual addresses, or floors or individual suites in buildings. If they were typically assigned to entire towns, there would be no point to them.
Zip Codes are only used in the United States. There are no international zip codes.
Numbers are used in zip codes.
Nigeria is composed of multiple states, each with multiple post codes. You can locate these for individual cities through the Nigerian Postal System website, linked below.
India does not have a single zip code for an entire state, as zip codes (known as PIN codes in India) are assigned to specific areas, towns, or cities. Andhra Pradesh, for instance, has multiple PIN codes depending on the locality. To find a specific PIN code in Andhra Pradesh, you would need to identify the particular city or area.
OK. States don't have Zip Codes. Cities have Zip Codes. You can get the complete list of ZIP codes in California under different Cities from here: http://www.zip4all.com/california/ca/ .
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.