The idea of modern zip codes of United States of America began in 1962 and was put into implementation in July of 1963. ZIP code is an abbreviation for Zoning Implementation Plan. The coding assigns a five digit code to cover every specific address of the country.
The first digit starts with the areas of northeast with 0 and ends with 9 specifying the west. The next two digits are generalizing smaller regions that have major haulage access. The last two digits represent smaller post offices or postal zones in large cities such as New York City or Los Angeles etc. in 1963 the new code was not implemented in all the country but it was ordered to be implemented countrywide in 1967. And the mailers were required to organize mail by ZIP code.