2021 A to Z: Letter Z
Zip Code Day (July 1)
Postal codes were used in various parts of the world and some areas of the US since the early 1900s.
Most major cities were using some form of postal code by the end of World War II.
Around that same time the idea of a Zone Improvement Project (ZIP) code was introduced in the US.
The ZIP plus two-letter state abbreviations was the brainchild of Henry Bentley Hahn, Sr., a postal inspector.
But the ZIP code’s 5-digit sequence went national in the US on July 1, 1963.
Did you know that Mr. Zip was used as the post offices’ promotional campaign?
Find out more postal fun facts at the National Postal Museum, part of the Smithsonian!
Celebrate Zip Code Day
Some communities also celebrate their own ZIP Code Days on dates that match their ZIP codes. For example, Mount Vernon, IA, with ZIP code 52314, celebrated on May 23, 2014. Their celebration included a block party, parade and sealing of a time capsule, to be opened at the town’s next ZIP code celebration, on May 23, 2114.