Which of these U.S. states has a postal abbreviation whose letters are not in alphabetical order?
Mississippi
Missouri
Minnesota
Michigan
On July 1, 1963, the Post Office Department introduced the five-digit ZIP Code. To make room for the ZIP Code in the last line of an address, state names needed to be abbreviated. Previously, the Post Office Department preferred that state names be written in full to avoid confusion. The department adopted the current two-letter abbreviations in October 1963. Michigan’s postal abbreviation (MI) is not in alphabetical order. Mississippi (MS), Minnesota (MN), and Missouri (MO) all have two-letter abbreviations that are in alphabetical order.
The correct answer is Michigan.