
We have religiously written our zip codes while sending our packages across the country. We already know that zip codes help determine the location of the person we wish to send the package to. Ever wondered what each letter of those 5-letter codes means? Sending and receiving postcards, packages or any other forms of confidential documents through USPS takes a lot of effort. As millions of mails are sent every day, the information you put up as the address must be accurate. As zip codes play a major role in determining the address of both the sender and the receiver, there’s a lot more to it than it seems. To help you understand zip codes better, this article will cover the USPS Zip code lookup, what do they mean, and how to use them efficiently.

USPS Zip Code Lookup
What Is USPS Zip Codes/Postal Codes?
As the United States Postal Services is the most used postal service to send everyday mails, they largely depend on the zip codes to sort millions of incoming mails. Zone Improvement Plan, otherwise known as a zip code, is a code that determines the postal address of a person living in any part of the world. This postal code comprises a series of unique numbers in a specific format that is used to describe the geographical location of a person. Every country has a postal code that has many names. In the United States, the postal codes are called Zip Codes.
Zip stands for Zone Improvement Plan, which is used to mark the precise geographic location of the destination address so that USPS can send the mails accurately. These 5-digit codes are used to represent the postal offices in the United States. In the United States, the postal code system is of two types: ZIP and ZIP + 4 code.
- The ZIP code, as mentioned already, is a 5-digit code
- The ZIP + 4 code is followed by a hyphen right next to the ZIP code. This code gives a rather precise location
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How to Read a USPS Zip Code?

ZIP Code
The Zip codes comprise 3 major components, i.e., the national area, the large city post office, and the delivery area. The national area is structured into 10 parts where each segment of the country is represented by a digit from 0-9. Once the national area is assigned, the next two numbers refer to the largest city. So, the first three digits of the zip code refer to as the sectional center facility. This facility is responsible for distributing the mails to a specific area within the city. Then comes the last two digits which are known as the delivery area or the associate post office code. This code refers to a particular town or city to which the mail is supposed to be delivered.
ZIP + 4 Code
The ZIP + 4 code for the United States was introduced in the year 1983 to provide a specific location, which made finding the geographic location a lot easier than it initially was. The zip+4 code was an additional 4-digit code attached to the already existing 5-digit postal code, forming a 9-digit code. Although these additional codes aren’t a necessity, they are used to identify a small street or an apartment, etc. Although every postal office has a zip+4 code, some USPS deliverable addresses do not have a zip+4 code. For these addresses, the USPS provides specific geocodes.
USPS Zip Code Lookup Tool: What Is My Zip Code?
To check for an accurate address while sending a package, you can do it through the USPS zip code lookup. With the USPS zip code lookup, you can find the zip code information of any major or minor area, city, or town and the zip+4 code as well. The USPS zip code lookup tool helps find the following addresses:
- A corporate or a residential address
- You can find the zip codes after entering the name of the city or the states
- Enter the zip codes and view all the cities that are enlisted within the specific zip code

USPS Zip Code Lookup-Find by Address
- If you wish to find the corporate or any residential address, you can do so by entering the name of the city, and state along with the street address
- Or you can simply enter the street address and the zip code to find the accurate address
- Additionally, you can also enter the name of the company/apartment for more accuracy
- Once done, click on Find
Find By City and State
- To find the zip codes, all you need to do is enter the name of the city and the state
- Click on Find to find all the zip codes that are within that city
Find Cities by Zip

Enter the zip code and click on Find. The following list includes all the cities in alphabetical order that are within the zip code.
Problems Associated With the USPS Zip Code Lookup Tool?
As zip codes are a very crucial part of a mail delivery system, it is important to ensure that the data entered on the mail should be verified. Although the USPS lookup tool helps find reliable data, sometimes you may come across information that might not be correct. All the addresses present in the software are updated by AMS software. If you find any issues/errors in the software, the errors are likely due to the addresses not being updated by AMS. You might encounter the following issues:
- The Address Is Misspelled on USPS Zip Code Lookup Tool: If you encounter any error in the spelling of any address on the USPS website, then you can contact the local Post Office and request for correction.
- The Recently Changed Zip Code Does Not Appear on the Site: All the nation’s addresses are maintained by the Address Management System (AMS). Any significant changes made to the addresses will only come into effect after the local AMS has made a change, which will reflect upon the website within 30 days.
- USPS Zip Code Lookup Tool Does Not Identify the Valid Address: If the software does not seem to identify the valid address, then you can try contacting the local post office and address your issues.
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What Can You Use Zip Codes for Other Than Delivering Mails/packages?
Although most people tend to think that zip codes do not hold enough value besides using them for delivering mails, zip codes play other important roles too. In addition to providing the location, they also act as a means to provide the demographics of people living in a particular region. Companies use zip codes to help find their target audience. Through zip codes, the companies can make the right marketing decisions such as setting up stores, or launching their services in new areas, etc.
Getting a Unique Zip+4 Code
The USPS allows companies to get a unique ZIP+4 postal code. Through the Business Reply Mail service, the USPS allows businesses to send return envelopes to their customers. Follow the steps below to get a unique Zip+4 address for your company:
- Log in to the Business Customer Gateway with your account
- Register the members and the company online
- Go to Business Reply Mail>Automated Business Reply Mail> Add Zip+4 Code
- Enter the complete address and fill in any required fields
- Submit the request and the delivery information will be sent to you
History of Zip Codes in the USA
Before the zip codes came into place, people delivered mail through stagecoaches, wagon rails, and steamboats. These mails were delivered to all parts of the country, from the most established areas to the military forts and settlements. When the majority of the population decided to serve the country during World War II, there was a sudden shortage of postal employees. With the increase in the number of mails, the USPS employee, Robert Moon decided to come up with a unique way to deliver the mail more efficiently. He proposed an idea to divide the largest cities into 124 delivery regions. Although this idea was discarded initially, 20 years later Postmaster General Edward Day decided to give it a try.
As the number of mails was considerably increasing, USPS decided to take up the idea of implementing a new mail delivering system. Mail processing centers were established on the outskirts of the nation to prevent long journeys. With the rise of the mail processing centers, the use of trains saw a reduction as people started to rely on airways to deliver the mails. During this phase, the mails delivered on an everyday basis weren’t just residential, but there was also a rise in business mails. The official announcement of the Zip codes was made on July 1, 1963. Although the use of these codes was not considered compulsory, in 1967, they became mandatory. The USPS also added an extra layer of convenience with the ZIP+4 code.
Fast-forwarding to the current period, these zip codes play a very crucial role in determining the address. For more efficiency, the USPS also has software that lets you find out the accurate details of any destination.
Fun Facts of the Zip Codes
- The lowest value for a zip code is 00501 which is the code for Internal Revenue Services in Holtsville
- The highest zip code value is 99950 which is the code for Ketchikan, Alaska
- One of the easiest zip code is 12345
- According to USPS, every zip code has approximate of 7,500 people
- The President and the first family has a secret zip code that no one has any knowledge of
Zip Codes in Other Countries
- Although most countries use zip codes, some necessarily do not need to have a zip code. That’s because of the size of the geographical location. For example, UAE. For countries that do not have a zip code, they simply mention the address and other details.
- Most countries follow a numeric system to identify zip codes, but some countries like the UK use a combination of both letters and numbers to identify the zip codes. Canada also uses the same form of alphanumeric system to represent the zip codes.
- In Australia, the zip codes are called as “postcodes”. There’s a total of 4 digits, the first digit identifies the state and the rest of the digits represent the cities
Conclusion
Zip codes are a major source of identification while delivering the mails in most countries. Every country has a different approach towards deciding the zip codes, and they are also referred to by different names. If you are facing any difficulty in finding the zip codes online, then you can always refer to the USPS Zip code lookup tool as it helps in providing the right details. Also, if you encounter any error while looking for the address on USPS, then you can contact the Post Office to get them clarified. Learn to order stamps online from here.
Frequently Asked Questions(FAQ’s)
Yes, the hyphen is an important character that needs to be placed in between the zip code and the zip+4 code. If the zip code is not proper, then the delivery might be slow or, at times, it may be sent back to the sender.
While navigating the addresses on the USPS Zip code lookup tool, if you seem to encounter an issue, then you can contact the Post Office and request a change.
Unfortunately, USPS does not store any foreign data on its website. To get any postal details, you need to either search it online or contact the postal services of the country.