On July 1, 1963, the United States Postal Service started using ZIP codes. A ZIP (Zone Improvement Plan) code is a five-number sequence printed after the city and state on all mail sent in the United States. The ZIP code was created to make processing the mail faster and more accurate. The first digit of a ZIP code represents a collection of states, the second two digits represent a more specific state or region, and the last digits represent the most specific delivery area for that region.

Today, many areas in the U.S. use the “ZIP+4” code, which adds an additional four numbers to the original ZIP code. These numbers give the postal service an even more specific location for the address within the ZIP code.


any area on Earth with one or more common characteristics. Regions are the basic units of geography.


to put in order.


exact or precise.


political unit in a nation, such as the United States, Mexico, or Australia.