U.S. State Abbreviations

Instructor: Elisa Goldman

Elisa has taught K-6 grades and has two master's degree in Instructional Technology and Education.

Each state has its own unique shortcut to make it easier for people to truncate the state names. In this lesson, you will learn about the standard and postal codes for each U.S. State and a brief history of state postal code abbreviations.

What Is My State Abbreviation Again?

The United States is made up of fifty states and a national capital, as well as a number of possessions and territories around the world. Because their names are often long, they are frequently abbreviated in written documents and on mailing addresses.

1973 Zip Code stamp


In 1831 and 1874, the United States Postal Service published a preferred list of state abbreviations. However, before 1963, the Post Office Department favored people writing out the state and territorial names in full to avoid confusion. For example, Mississippi and Michigan might both be abbreviated MI for their first two letters.

In 1963, the post office put into effect the five-digit ZIP Code which would be written after the state abbreviation. At this time, many state abbreviations were made up of four letters. However, due to limited space availability on mailing labels, it was felt that the four letter abbreviations combined with the five-digit zip code contained too many digits. As such, the state abbreviations were amended in October 1963 to the now familiar two letters.

The change-over to the two-letter state abbreviations was not instantaneous. At first, they were optional and intended for use by large businesses to use in conjunction with the new zip codes. To date, there has only been one change to the abbreviations. In 1969, the postal abbreviation for Nebraska, NB, was changed to NE at a request from the Canadian Postal Administration, in order to avoid confusion with the province of New Brunswick. The United States territories and oversees military installations were also given their own two-digit abbreviations.

Military 'State' Abbreviations

Have you ever heard of APO or FPO mailing addresses and wondered what they were? Well, they are how mail is sent to military personnel stationed overseas. APO is an acronym (you know the military loves their acronyms) for Army Post Office (includes the Army & Air Force), while FPO stands for Fleet Post Office (includes the Navy and Marine Corps). These abbreviations take the place of a city name, and then must be used with a 'state' abbreviation of 'AA' (Armed Forces Americas), 'AE' (Armed Forces Europe), or 'AP' (Armed Forces Pacific). These addresses also utilize special zip codes.

Map of United States

List of State Abbreviations

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