United States ZIP codes are a form of postal code used in the United States to allow the United States Postal Service (USPS) to make the mail system more efficient. Some people still call a ZIP code USA a “US postal code” because of this origin. The “ZIP” in ZIP Code stands for “Zone Improvement Plan”. The basic five-digit ZIP code was introduced in 1964 before expanding with a dash and further four digits to create a “ZIP+4” code. These extra four digits help the USPS deliver mail more precisely.
What are ZIP Codes?
While ZIP codes were originally developed for USPS, many shipping companies take advantage of these cods, including United Postal Service (UPS) and FedEx. These codes help couriers determine the shipping rate for goods – the cost and time for shipping. Please note that some state postal authorities have unique ZIP code systems.
Five-digit ZIP codes are also called area codes. The system assigns a particular geographic region or collection of locations with similar geographical features. For example, every post office in Phoenix, Arizona, is assigned a ZIP code, even ones outside of the metropolitan area. Similarly, every post office in Hinesville, Georgia, is assigned a ZIP code.
There are some variations for these ZIP codes, including codes without a hyphen prefix. These codes are used for states without five-digit ZIP codes. There are also some codes with two-letter combinations, such as 40074 for Hillsboro in Oregon.
In general, postal codes are standardized within each state, with the exceptions of Arizona and Texas. Every post office accepts addresses in the standard ZIP code so long as they have been assigned consistently. Some ZIP codes are incorrect for particular communities because of population differences and address duplication.
Special ZIP Codes
The US Military is something of an exception to the rule. US Military addresses use nine-digit ZIP codes. These codes are used to deliver mail across army bases and installations. Each unit has a unique nine-digit number, making it easier to determine where mail should go. The military refers to each of these bases as installations instead of addresses, so some military units have a two-letter ZIP code.
The United States Postal Service also uses other codes for special addresses. These special codes and addresses can all be found on the USPS website with the locator tool. You can also use the tool to find the ZIP code for your area if you aren’t sure what it is.
The Future of ZIP Codes
Some states are beginning to phase out ZIP Codes. For example, New York City introduced plans where customers would submit their exact address rather than providing their ZIP code. Mail would be sent to their physical address using their street address. While these systems aren’t wholly uniform yet, more and more places are adopting them.
Of course, the United States isn’t the only country to use ZIP codes/postal codes. Many other countries, including the UK, take unique approaches to the system that work for them.