What is a zip code?

A ZIP Code is a postal code used by the United States Postal Service (USPS). Zip codes where introduced in 1963 and the format consisted of five digits. In 1983, an extended ZIP+4 code was introduced. This included the five digits of the original ZIP Code and followed by a hyphen and four digits that designated a more specific location.

What is the lowest ZIP Code?

Alas, the lowest zip code isn't a single digit or in possession of the Supreme Court or other such group. The lowest in-use zip code is 00501 and it belongs to the IRS mail processing center located in Holtsville in New York.

What is the highest ZIP Code?

The highest ZIP Code is 99950, belongs to the city of Ketchikan in Alaska.

How many ZIP Codes are there in the US?

There are 41,692 around ZIP Codes in the US. ZIP Codes range from 00501, belonging to the Internal Revenue Service in Holtsville, NY, to 99950 in Ketchikan, AK.

What is a ZIP+4 code?

The ZIP+4 code is used and assigned by the United States Postal Service (USPS) for especially routing purposes. The final 4 digits are not required for delivery of mail and can change frequently.