We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is the Purpose of Zip Codes?

By Christina Edwards
Updated May 17, 2024
Our promise to you
America Explained is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At America Explained, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

In the United States, ZIP codes are a type of postal code. Individuals who mail letters or packages via the United States Postal Services (USPS) are required to write the code as part of the address. This five-digit code helps ensure that parcels get to their intended destination faster. In fact, the acronym zip, which stands for Zone Improvement Plan, suggests speed and swiftness.

By looking at the numbers in these codes, a mail sorter can determine where the parcel should go. Each digit in a ZIP code stands for specific areas or regions of the United States (US). Some stand for broad regions, such as the east or west coast, while others stand for specific states, cities, and towns.

The first digit of each code corresponds to a broad regional area. Typically, this is a group of neighboring states. For example, codes beginning with zero represent the New England states, including Maine, Massachusetts, Vermont, and Connecticut. They also represent US territories, like Puerto Rico and the US Virgin Islands.

Zip codes that begin with the number nine, on the other hand, typically represent states along the west coast. California, Oregon, and Washington all have codes that begin with nine, for instance. Alaska and Hawaii also have zip codes that begin with nine.

The next two digits represent a specific sectional center facility. These USPS facilities are responsible for sorting the mail even further. Many times, they are located in large metropolitan areas.

The last two digits represent an even more specific area, usually a post office. This is located within the region represented by the first digit. It is also typically close to the sectional center facility.

Some addresses that manage a large volume of incoming mail may have their own zip codes, known as unique zip codes. For example, the White House has the zip code 20006. Other government buildings in the US also have been assigned codes that start with 202 through 205, regardless of where they are located. Universities and other similar facilities may also have unique postal codes.

Although it is not required, sometimes a parcel is addressed using nine-digit codes. This type of code is sometimes referred to as a ZIP+4 code. These codes are written with the first five digits, followed by a hyphen, followed by the additional four digits. These last four numbers narrow a location down even more, and many times they represent a specific block or street.

America Explained is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By Reminiscence — On Apr 24, 2014

I know how bad my own handwriting can be, so I'm surprised that more mail isn't misdirected because of an illegible number or two. The mail handlers and sorting computers must be used to interpreting squiggly lines pretending to be numbers.

By RocketLanch8 — On Apr 23, 2014

I can see where a zip code would be an efficient way of sorting the incredible volume of mail that arrives at a postal facility. One employee wouldn't have to know what each and every number represented. The first mail handler would just look at the first number and send it to the corresponding bin. The process would be repeated at the next facility, where another handler would only care about the next two numbers, and so on. It's better than relying on one handler to read all five numbers at once.

America Explained, in your inbox

Our latest articles, guides, and more, delivered daily.

America Explained, in your inbox

Our latest articles, guides, and more, delivered daily.