ZIP Codes in the USA, often referred to as “Zone Improvement Plan” codes, were introduced in 1963 to simplify and expedite mail delivery. A ZIP Code is a five-digit number that generally identifies a delivery area, such as a city, neighborhood, or specific post office. The first digit of a ZIP Code indicates the geographic region.
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How to Find a ZIP Code in the USA
You can look up a ZIP Code on the United States Postal Service website.
To find the correct ZIP Code, simply enter the address of the location. You can also search by entering the combination of a city and U.S. state, or reverse-search a location associated with a specific ZIP Code.
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What Is a ZIP Code in the USA?
✉️ How ZIP Codes Work
The basic ZIP Code format consists of five digits, which can indicate the location of the area. For example, ZIP Code 90254 for Hermosa Beach identifies California (9) and the Inglewood distribution center (902).
Since 1983, the extended “ZIP+4” format has been widely used. This version helps pinpoint a specific location more accurately. For example, packages sent directly to a post office typically use ZIP Code 9998, while 9999 is used for “general delivery,” meaning the package will remain at the pick-up location.
The term “ZIP Code” is a registered trademark of the United States Postal Service (USPS).
🖊️ How to Correctly Write a ZIP Code in the USA
In the address line, the ZIP Code is written after the city and state without a separating comma, for example: Hermosa Beach CA 90254-3552.
📋 ZIP Code Assignment System
ZIP Codes are assigned based on a system that reflects the geographical layout. The first digit specifies the area, with zero representing the East Coast and nine the West Coast. The second and third digits narrow down the location, while the fourth and fifth identify a specific post office.
First Digit States and Territories 0 Connecticut, Massachusetts, Maine, New Hampshire, New Jersey, Puerto Rico, Rhode Island, Vermont, Virgin Islands, Army Post Office Europe (AE), Fleet Post Office Europe (AE) 1 Delaware, New York, Pennsylvania 2 District of Columbia, Maryland, North Carolina, South Carolina, Virginia, West Virginia 3 Alabama, Florida, Georgia, Mississippi, Tennessee, Army Post Office Americas (AA), Fleet Post Office Americas (AA) 4 Indiana, Kentucky, Michigan, Ohio 5 Iowa, Minnesota, Montana, North Dakota, South Dakota, Wisconsin 6 Illinois, Kansas, Missouri, Nebraska 7 Arkansas, Louisiana, Oklahoma, Texas 8 Arizona, Colorado, Idaho, New Mexico, Nevada, Utah, Wyoming 9 Alaska, American Samoa, California, Guam, Hawaii, Marshall Islands, Federated States of Micronesia, Northern Mariana Islands, Oregon, Palau, Washington, Army Post Office Pacific (AP), Fleet Post Office Pacific (AP) -
Interesting ZIP Codes in the USA
00501
The lowest ZIP Code in the USA is assigned exclusively to the Internal Revenue Service in Holtsville, New York.
06390
Although Fishers Island is part of New York State, its only access is by ferry from Connecticut. This also applies to its mail, which is assigned a Connecticut ZIP Code.
10001
ZIP Code 10001 is home to the largest number of businesses and companies (around 7,200) and belongs to the Chelsea neighborhood in Manhattan.
12345
This unique ZIP Code is used by General Electric in Schenectady, New York.
20252
This ZIP Code is reserved for Smokey Bear, the mascot of the U.S. Forest Service. Smokey Bear became the face of a campaign to recruit junior rangers. Due to the high volume of incoming mail, the USPS assigned this unique ZIP Code to the mascot in 1964. The ZIP Code formally belongs to Washington, D.C.
20500-0001
This ZIP+4 Code is exclusively reserved for the sitting President of the United States. The First Lady has her own ZIP Code, 20500-0002. The standard ZIP Code for the White House is 20500.
90210
This ZIP Code became famous due to the television series *Beverly Hills, 90210*.
99950
The highest ZIP Code in the USA belongs to the Ketchikan area in Alaska.
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