This week marks the 50th anniversary of the Zone Improvement Plan the network of ZIP codes we use for everything from mail delivery to credit card security.
The U.S. Postal Service began using the five-digit codes on July 1, 1963, hoping they would improve the efficiency and speed of mail sorting. Since then, the codes have assumed a role in the identities of many Americans, helping to define where they live or work.
In recognition of the anniversary (and because we are geeky), we've examined the list of more than 40,000 ZIP codes. Here are nine worth noting, based on data compiled by the U.S. Census Bureau and Esri, a leading geographic software company: