US Zip Code - Postal Codes United State
Find US zip code system works all around the country. It has five-digit numerical code directs mail through regions, states and specific neighborhoods. Explore how the postal system assigns these numbers. Understand the different zip code formats used nationwide.
US ZIP Code
The United States Postal Service (USPS) created the zip code system on July 1, 1963. Today the nation relies on roughly 38,000 zip codes to deliver mail efficiently. These codes can cross county lines and state borders to speed up processing routes.
A standard five-digit zip code uses a simple structure to guide your mail.
- The first digit represents a national region that includes a specific group of states
- The second and third digits point to a smaller region or sectional center within those states.
- The fourth and fifth digits identify a specific group of delivery addresses, local post office, or neighborhood.
Under this system central cities within a region usually receive the lowest numbers, often ending in '01'. The postal service then assigns the following numbers to surrounding towns.