Happy 50th Birthday, ZIP Codes!

The ZIP code is 50 years old, which means today is the day to take some time to learn about those five little digits we all take for granted. We’ll start with the basics: learning what this acronym means. ZIP stands for Zoning Improvement Plan, and it was put into place in July of 1963 as a way to manage the extreme increase in the amount of mail being sent around the country. If it feels like ZIP codes have not been around for quite 50 years, it’s because the Post Office Department only started requiring people to use them in 1967.

According to the United States Postal Service (USPS), the largest American cities were given zoning codes in 1943 because so many postal employees joined the military at the time. This left the steadily growing mail industry shorthanded when it came to experienced staff, so a system was created to make the mail a little faster to sort. The primitive zoning codes only had one or two numbers to differentiate cities, but by 1962, the Post Office Department had come up with a more advanced system. Each address in the country was given a code with five digits, and by July 1, 1963, people were encouraged to use their ZIP code to ensure delivery of their mail.

Starting in the 1960s, the importance of the mail system was growing, mainly due to the advent of the computer. So although mail and technology might not seem to go hand in hand, the computer actually had a direct role in the growth of this industry because it allowed businesses to send bills, advertisements, and catalogs in bulk through the mail. It also let individuals send payments, receive checks, and sign up for magazine subscriptions. There was a clear need to simplify the mail sorting process, and ZIP codes and computers made that possible.

Not surprisingly, there is nothing random about your ZIP code, since each digit has an important meaning. The first one indicates which region of the U.S. you live in, with zero being the assigned number for the Northeast and nine representing the West Coast. The next two digits of your ZIP code provide a more detailed description of where you live, since they indicate the region or major city you reside in within your state. The last two digits of the ZIP code refer to the specific Post Offices that serve your area.

These days, it is common to not only know the ZIP code of your current home, but also remember those associated with past residences. After all, this number says a lot about where you live. The Census Bureau even breaks down demographic information by ZIP code, and some areas are easily recognized simply by this number. Beverly Hills and its 90210 zoning code is just one example.

No matter what your ZIP code is, it deserves to be celebrated on its 50th birthday.