The ZIP Code is the system of postal codes used by the United States Postal Service (USPS). The letters ZIP, an anacronym for Zone Improvement Plan, are properly written in capital letters and were chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the code in the postal address. The basic format consists of five numerical digits. An extended ZIP + 4 code includes the five digits of the ZIP Code...
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The ZIP Code is the system of postal codes used by the United States Postal Service (USPS). The letters ZIP, an anacronym for Zone Improvement Plan, are properly written in capital letters and were chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the code in the postal address. The basic format consists of five numerical digits. An extended ZIP + 4 code includes the five digits of the ZIP Code, a hyphen, and four more digits that determine a more precise location than the ZIP Code alone. The term ZIP Code was originally registered as a servicemark (a type of trademark) by the U.S. Postal Service, but its registration has since expired.
The United States Post Office Department (USPOD) implemented postal zones for large cities in 1943. For example:
The "16" is the number of the postal zone within the city.
By the early 1960s a more general system was needed, and on July 1, 1963, non-mandatory ZIP codes were announced for the whole...
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