USPS zip code maps can be found by visiting the USPS website and inputting the street address, city and state. There is also an option to look up the zip code map by company or to view all of the cities within a particular zip code.
The zip code system began in the early 1960s. Today, the zip codes are used in sales and marketing applications, internet technology and data collection. When zip codes began, they were used to help determine where a piece of mail should be delivered. The zip code format consists of five digits and then the extended version includes the five digits along with a hyphen and four more digits.
In 1944, Robert Moon submitted his proposal for the zip code system while he was working as a postal inspector for the Post Office. However, Moon was only given credit for the first three digits of the five digit zip code. In 1963, non-mandatory zip codes were listed for the entire country. In 1967, these zip codes were made mandatory for all of the second and third class bulk mailers. Soon after that, the system was determined mandatory for all mailing items.
The zip code tabulation areas (ZCTAs) are real representations of the USPS zip code areas. They are generalized and are also put into a map form. They are created by first finding blocks and then assigning an entire census block to the zip code that occurs most often on the block.