What Is A Zip Code?


Zip Codes are an important tool that the logistics industry uses to make sure packages and letters reach their intended recipient. In this post, we explore the history and origin of Zip Codes as well as what each number in the Zip Code means.

Origins Of Zip Codes:

In 1963, the United States Postal Service introduced the ZIP code. ZIP stands for Zone Improvement Plan. Zip codes help to improve letter and packaging processing by standardizing the sorting process of mail-pieces. In the post-WW2 era, American business was booming and millions of packages and letters were being sent through a mail system that was designed in the 19th century. Due to this antiquated system, a backlog formed as the Post Office struggled to process this new found elevated volume of mail. The solution was proposed to add a number to the end of an address to simplify the sorting process. Before the ZIP code was introduced, sorters would have to read the entire address when sorting letters and packages to make sure they reached their intended destination. Now with the new ZIP code, mail could be sorted by simply referring to one simple 5 digit number.

Meaning Behind The Digits:

1st Digit: The first digit is often referred to as the area code or national area. As you move from left to right each number of the ZIP code becomes more specific. This first number ranges from 0-9 counting up from East to West and refers to a grouping of specific states. This is the first step in sorting, making sure that your letter or package is headed to the right area in the country. You can determine the destination region of the package or letter from just this single digit; for example, all Zip codes in Pennsylvania, Delaware, and New York begin with the number one.2nd & 3rd Digits: The second and third digits are referred to as the sectional center. This number corresponds to a sort center or large post office that processes and sorts packages and letters in bulk before sending out to local post offices for delivery.4th & 5th Digits: The fourth and fifth digits represent your local post-office or delivery area. This often refers to a town or in some cases a section of a city. This is the most specific location information in the standard 5 digit ZIP code. With just these 5 digits a package can find its way onto your local mail truck from an origin point anywhere in the world.Additional 4 Digits: We have all seen the four extra digits added onto our ZIP code and wondered what they mean. These additional digits get even more specific. The 6th and 7th digit refer to a specific street or building. The 8th and 9th digit refer to a section of the street or floor/section of a building.

Future Of ZIP Codes:

As the US population continues to grow so does the need for more and more specific coding within our ZIP Codes. There have been many suggestions made to improve the ZIP code system since the addition of the 4 additional digits in the 80s. One of the most common suggestions is using latitude and longitude lines much like a GPS to pin point an even more specific geographic location, but even this has its limits as we begin to expand into 3 dimensional spaces such as large office buildings. Although we do not know exactly what ZIP Codes will look like in years to come, it is safe to say we will continue to make progress in conveying more and more geographic information in a simple to understand format like the ZIP code.

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