A postal code is a five digit code used to help postal services deliver mail and packages. Here's what the numbers mean and how they determine yours.

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.

A new U.S. Postal Service tracker lets you see delivery statistics for yourself.

The Postal Service’s plans will delay a third of mail in 27 states, according to a Washington Post analysis, hitting states west of the Rocky Mountains especially hard.