Most Americans know their ZIP code by heart. They type it into online forms, scribble it on envelopes and memorize it as part of their address. But not everyone knows the original meaning of the term.

On July 1, 1963, the U.S. Post Office Department introduced the ZIP code program to get a handle on the heaping surplus of mail. Today, those five digits represent much more for American society. Back ...

The House passed two bills Monday night that would authorize the U.S. Postal Service to create 76 new ZIP codes for communities nationwide. This is not the first proposed ZIP code upgrade. In December ...