After the 5-digit ZIP code gets the mail to your local post office, the "plus 4" code gets it to your neighborhood. "Do you have to write it on your letters?" asked WCCO reporter Jason DeRusha.

Removing the necessity of city and state on envelopes and packages, and leaving it to a formulaic five-digit zip code improved accuracy of mail sorting, and quite frankly, greatly improved the speed ...

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.