US Zip Codes: How Postal Codes Work

1 - I can do better 2 - Jury's out 3 - Pretty darn good 4 - Splendiferous 5 - Awesometastic by 1 person | Log in to rate

Ranked #2,114 in How-To, #21,636 overall

Ever wonder what the ZIP in Zip Code stands for? Why do we append a string of numbers after our addresses? How do the letters and packages we send and receive actually find their way?

The ZIP Code system is a very interesting feature of present-day communication. Sure, it's not as hip as email, instant messaging, or SMS, but it's a really cool way of keeping all the things traveling by courier on the right track.

What's a ZIP Code? 

A ZIP Code is a 5-digit number representing a specific location somewhere in the United States. The extended ZIP + 4 code appends a hyphen and 4 additional digits for an even more precise location.

The ZIP Code system was introduced by the United States Postal Service in the early 1960s to route mail as quickly as possible.

Decoding the ZIP Code 

How does the ZIP Code system work?

Let's break down the parts of the modern-day ZIP code:

First Digit:
A group to which the ZIP code's state belongs. For example, if the first digit is 4, the ZIP code can be found in either Indiana, Kentucky, Michigan, or Ohio. The lower digits are found east and increase towards the west.

Second and Third Digits:
A region in the said group, chosen according to statistics such as the population or access to transportation. Combined with the first digit they make up a sectional center facility code, which is the headquarters for mail sorting and distribution in that region.

Fourth and Fifth Digits:
A more specific location in the said region. This could be an area in a city or a town.

ZIP Codes as Geographic Locations 

It must be stressed that ZIP codes were created primarily for more efficient routing of mail around the country. The postal system takes into consideration things like address groups and mail delivery routes. Therefore, it's not that easy to give a precise location from a ZIP code.

Nevertheless, it gives us some rough idea of where it is. The first three digits of the ZIP code hint at which state it belongs to.

Types and Uses of ZIP Codes 

Unique
Assigned to a single address that receives a large amount of mail.

P.O. Box Only
Assigned to a P.O. Box at the post office.

Military
Assigned to mail for the military.

Standard
Assigned to all other types of locations.

New Text List 

by L.L.

Love learning.
(more)

Explore related pages

Create a Lens!