Say what you want about the U.S. Postal Service; it knows how to run an effective promotional campaign. At least it did 50 years ago: That’s when it introduced the zip code. Along with the zip code, the Postal Service issued new two-letter state abbreviations.
Before the roll-out, people addressing mail wrote out state names in full, or abbreviated them using a style they had memorized in school: Tenn. and Calif. and W. Va.
In 1963, the Postal Service introduced two-letter state abbreviations, with uppercase letters and without punctuation. The Postal Service ran an ad campaign that lodged the new abbreviations into people’s brains.
The campaign, featuring the memorable character Mr. Zip, was one of the most successful in American advertising. Over time, the two-letter state abbreviation became so ingrained that people not only used the style for addressing their mail; they began using it every time they wrote the name of a state. Even in sentences.
That’s when people entered a state of confusion.
The two-letter, all-caps, punctuation-free state abbreviation was intended for the outside of envelopes and packages, to speed processing. Postal abbreviations do not belong in sentences.
When the name of a state stands alone in text, writers should spell it out:
The people of California have seen extreme weather lately.
When a city and state are referred to together, until now AP Stylebook advised writers to abbreviate the state using the traditional style:
The climate in Hollywood, Calif. is drier than the climate in Hollywood, Fla.
For the 2014 edition, AP Stylebook changed that. The “journalist’s bible,” as it calls itself, now advises writers to spell out state names in the body of stories. AP says the abbreviations should continue to be used in datelines, lists, tables, photo captions, and such.
The Chicago Manual of Style prefers spelling out the state name, even when it follows the city name. (In tables, bibliographies, and lists, Chicago prefers the two-letter postal abbreviation, allowing the traditional style as an option.)
Here are the traditional state abbreviations:
By the way, did you know ZIP is an acronym for zone improvement plan? AP Stylebook still tells us to write the 50-year-old ZIP in uppercase letters. Chicago uses lowercase letters for zip code, like it does for the acronyms radar and scuba. (This blog follows Chicago style. Some house styles use Zip, with an initial cap.) The AP Stylebook has accepted far newer usages – don’t get me started on the 2011 Stylebook’s hyphenless email – and I think it’s time for AP to put its stamp of approval on the lowercase zip code.