If you've been around for any length of time you know that the US Postal Service has made several changes in the way we address our mail over the years. These changes were set up to accommodate a constantly growing and changing population. The new systems were designed to speed up the sorting and delivery of mail in all parts of the country. So, in case you're wondering what does US Postal ZIP Codes +4 mean, this is what you should know.

The ZIP Code:

The term ZIP code is actually an acronym that stands for Zone Improvement Plan, which was initially set up in 1963 to help sort out the large quantities of mail that needed to be delivered. The nation was divided into Postal Zones that were each given a number across the nation. A ZIP Code is a 5-digit number that tells the mail service exactly which postal zone a piece of mail is coming from and where it is going.

The ZIP Code is always tied to a post office. One ZIP Code for each post office in the country is the standard. Each post office is a collection of different routes, which may or may not follow a specific geographic boundary so some ZIP Codes can cross city, county and even state lines if necessary. However, there are a few specialty ZIP Codes that do not have borders or boundaries. The MP Codes for example, include all mail delivered to military bases all over the world or to battleships at sea.

There are also what are called "unique" codes used for large businesses and organizations that receive such a high volume of mail that they have their own ZIP Code.

The ZIP Code +4:

So, what does US Postal ZIP Codes +4 mean? ZIP Codes can be very accurate when it comes to narrowing down a specific location a piece of mail needs to go. Each of the 5 digits in the Postal Code points to a designated area narrowing down a geological region from largest to smallest. The first digit points to a specific region or collection of states, the second two point to a postal zone, and the last two narrow it down even further to the exact post office that is charged with delivering the mail.

While the first 5 digits narrow down a destination to a specific town or city, the final 4 digits can narrow it down to a single block or spot within that city. It can be so precise that it points to a specific floor in a high-rise building or a specific side of a street.

It is beneficial to know what does US Postal ZIP Codes +4 mean. It not only can get your mail delivered to the recipient faster but those businesses using it for bulk mailing options can save money on their shipping costs. Overall, the ZIP +4 is the latest modification in the postal services mail delivery but as the population continues to grow and expand, there will be even more adjustments to learn about in the future.