A guide comparing Associated Press style and Chicago style for editors, writers, teachers, students, word nerds, and anyone else who gives a dollar sign, ampersand, exclamation point, and pound sign about style.

State Abbreviations: Use Traditional or Go Postal?

Update: Revised to reflect the AP's changes to its "state names" entry, effective 5/1/2014.

In this quick guide to state abbreviations, I will cover the differences between AP style and Chicago style and—just to prolong your state of confusion—when to use the common two-letter abbreviations created by the United States Postal Service.

If you're writing a research paper or dashing off a blog post, you can probably ignore all the exceptions and special cases and just memorize these basic guidelines:
  • In running text, AP and Chicago both spell out state names.
  • For mailing addresses, AP and Chicago both default to the two-letter postal abbreviations.
  • For all other abbreviations, AP uses its own state abbreviations and Chicago prefers postal abbreviations (but has its own state abbreviations should that style be more appropriate for your publication).

Did that little appetizer leave you wanting more? If so, I love you. And please read on for an expanded version of the brain-twisting details.

AP (online, fee required):
  • Spell out state names in running text.
  • Abbreviate state names when used in (1) datelines on stories (e.g., "KOSHKONONG, Mo."), (2) photo captions, (3) lists, (4) tables, and (5) short-form listings of party affiliation (e.g., "D-Calif."). (Refer to AP's "datelines" entry for use of certain well-known city names alone.)
  • Use two-letter postal abbreviations only in mailing addresses which include a zip code: "To complain about AP style, write to The Associated Press, 450 W. 33rd St., New York, NY 10001."
  • For headlines, the new rule says to avoid abbreviating states whenever possible, and the old rule—in case you can't avoid abbreviating—said to lose the periods when using abbreviations which consist of two capital letters: "NY" but "Ky."
Chicago (10.28):
  • Spell out state names when they stand alone in running text: "I don't see why Kansas and Arkansas can't make their names rhyme."
  • Spell out state names when used with the name of a city (except for "DC"): "I was born in New York, New York—no, please don't sing."
  • Two-letter postal abbreviations are preferred over traditional abbreviations when state names are used in bibliographies, tables, lists, and so on.
U.S. Postal Service:

Following are the differences between AP and Chicago style in how state names are rendered in their respective "traditional" abbreviations. (Surprise! Abbreviations are not always used.) Use Command-F or Ctrl-F to perform searches. That's right, it's ugly for a reason.

Aside #1: If your quality expectations are sufficiently lax, as are mine, you might enjoy Wikipedia's version of how state abbreviations evolved and come up with your own explanation for why there are different notions of what's "traditional." Don't bother consulting the stylebooks' official dictionaries for the proper abbreviations: Those are more descriptive than prescriptive and will only confuse you with more options.

Aside #2: The two-letter U.S. Postal Service code is listed parenthetically after the complete state name, but you probably figured that out.

Aside #3: Note that none of the two-word abbreviations have a space after the first period, e.g., "N.Mex." and "R.I."

Reminder to those who thought they were being smart by skipping straight to this list: Chicago prefers the two-letter postal abbreviations over traditional abbreviations; all options are listed below.

Alabama (AL)
  • Both: Ala.
Alaska (AK)
  • AP: Alaska
  • Chicago: Alaska or Alas.
Arizona (AZ)
  • Both: Ariz.
Arkansas (AR)
  • Both: Ark.
California (CA)
  • Both: Calif.
Colorado (CO)
  • Both: Colo.
Connecticut (CT)
  • Both: Conn.
Delaware (DE)
  • Both: Del.
District of Columbia (DC)
  • AP: District of Columbia
  • Chicago: D.C.
Florida (FL)
  • Both: Fla.
Georgia (GA)
  • Both: Ga.
Hawaii (HI)
  • Both: Hawaii
Idaho (ID)
  • Both: Idaho
Illinois (IL)
  • Both: Ill.
Indiana (IN)
  • Both: Ind.
Iowa (IA)
  • Both: Iowa
Kansas (KS)
  • AP: Kan.
  • Chicago: Kans.
Kentucky (KY)
  • Both: Ky.
Louisiana (LA)
  • Both: La.
Maine (ME)
  • Both: Maine
Maryland (MD)
  • Both: Md.
Massachusetts (MA)
  • Both: Mass.
Michigan (MI)
  • Both: Mich.
Minnesota (MN)
  • Both: Minn.
Mississippi (MS)
  • Both: Miss.
Missouri (MO)
  • Both: Mo.
Montana (MT)
  • Both: Mont.
Nebraska (NE)
  • AP: Neb.
  • Chicago: Neb. or Nebr.
Nevada (NV)
  • Both: Nev.
New Hampshire (NH)
  • Both: N.H.
New Jersey (NJ)
  • Both: N.J.
New Mexico (NM)
  • AP: N.M.
  • Chicago: N.Mex.
New York (NY)
  • Both: N.Y.
North Carolina (NC)
  • Both: N.C.
North Dakota (ND)
  • AP: N.D.
  • Chicago: N.Dak.
Ohio (OH)
  • Both: Ohio
Oklahoma (OK)
  • Both: Okla.
Oregon (OR)
  • AP: Ore.
  • Chicago: Ore. or Oreg.
Pennsylvania (PA)
  • Both: Pa.
Rhode Island (RI)
  • Both: R.I.
South Carolina (SC)
  • Both: S.C.
South Dakota (SD)
  • AP: S.D.
  • Chicago: S.Dak.
Tennessee (TN)
  • Both: Tenn.
Texas (TX)
  • AP: Texas
  • Chicago: Tex.
Utah (UT)
  • Both: Utah
Vermont (VT)
  • Both: Vt.
Virginia (VA)
  • Both: Va.
Washington (WA)
  • Both: Wash.
West Virginia (WV)
  • Both: W.Va.
Wisconsin (WI)
  • AP: Wis.
  • Chicago: Wis. or Wisc.
Wyoming (WY)
  • Both: Wyo.

Chicago also lists other U.S. territories, only two of which have traditional abbreviations (Puerto Rico and Virgin Islands). None of these are abbreviated in AP style, except in mailing addresses.
  • American Samoa (AS)
  • Federated States of Micronesia (FM)
  • Guam* (GU)
  • Marshall Islands* (MH)
  • Northern Mariana Islands (MP)
  • Palau (PW)
  • Puerto Rico* (PR): P.R. or Puerto Rico
  • Virgin Islands* (VI): V.I. or Virgin Islands
*Check entry in the Associated Press stylebook for more details.

    And why the hell not, here are the USPS military "state" abbreviations:
      • Armed Forces Africa (AE)
      • Armed Forces Americas, except Canada (AA)
      • Armed Forces Canada (AE)
      • Armed Forces Europe (AE)
      • Armed Forces Middle East (AE)
      • Armed Forces Pacific (AP)

      Final tip: It might help to know that AP's standard abbreviations are shorter than (or the same as) Chicago's for all U.S. states except Alaska and Texas. Well, we might as well throw in District of Columbia. And, if feeling generous, Puerto Rico and Virgin Islands. Or, in favor of keeping your brain less cluttered, you can bookmark this page and forget everything you just read.

      Update: The list is now downloadable! You're still coming back to visit, right?

      State Abbreviations: The Difference Between AP and Chicago Styles


      1. This is actually really informative. The lack on consistency has always annoyed me, but this explained that there is at least rules, instead of what always seemed like raw sloppiness

      2. Anyone know the correct way to abbreviate the Upper Peninsula of Michigan (UP or U.P.)?