USPS logo LINK — USPS employee news Printable

ZIP ZIP hooray!

The list: 7 facts about ZIP Codes

Black and white photo of man in suit and two men in uniforms
PMG J. Edward Day and two letter carriers stand near a display of Mr. ZIP artwork in 1963.

You see ZIP Codes every day, but how much do you know about them? “The list” is here to help you sort it all out.

1. “ZIP” stands for “Zoning Improvement Plan.” The five-digit codes were introduced in 1963 and assigned to every address in the nation to better sort and deliver mail.

2. Mr. ZIP helped promote the codes. During the 1960s, the popular cartoon figure appeared in advertisements encouraging customers to use ZIP Codes on mail.

3. ZIP+4 was launched in 1983. The extra four digits help identify carrier routes and address blocks.

4. There are almost 42,000 ZIP Codes. You can use ZIP Code Lookup, an online tool, to search codes by address or city and state.

5. ZIP Codes go high and low. Ketchikan, AK, has the highest ZIP Code: 99950. The lowest code, used for the Internal Revenue Service in Holtsville, NY, is 00501.

6. At least one ZIP Code floats. The J.W. Westcott II, a 45-foot Detroit River mail boat that delivers to passing ships, has its own ZIP Code: 48222.

7. General Electric has the nation’s easiest to remember ZIP Code. The code for the company’s location in Schenectady, NY? It’s 12345.

Got ideas for future editions of “The list”? Email them to

Post-story highlights