Iowa Abbreviation: IA and How to Use It

IA, Ia. and Iowa side by side

The right choice hinges on where your words will land. This short guide covers the usual cases.

The pattern is simple. Machines and mail carriers like IA. Human readers like Iowa.

Why the Iowa abbreviation is so rarely needed

Most traditional state abbreviations, such as Mass. or Calif., exist to save space on long names. Iowa is already short, so the old form Ia. saves only two characters. That is why the news style many papers follow spells out every state in running text and lists Iowa among eight short names it never shortens, not even in datelines. The other seven are Ohio, Utah, Texas, Maine, Idaho, Hawaii and Alaska.

If you are filling in a form with a two-letter state box, though, IA is the only right answer. Typing "Iowa" there may be rejected or cut off.

How to write the IA state abbreviation on mail

Mail sorts best when IA is printed in capitals, with no period and a single space before the ZIP code:

A few habits help mail move quickly:

• Keep IA in capitals. "Ia" or "ia" can confuse sorting machines.
• Leave off periods. "I.A." is not a postal form.
• Check the ZIP code. Iowa ZIP codes begin with 50, 51 or 52, so a code that starts with 46 or 60 points to a different state.

Every other state's code appears in our state abbreviations chart.

Letters that look like IA

Four state codes start with I, and they get mixed up often, especially by people typing fast:

• IA: Iowa
• ID: Idaho. See the Idaho abbreviation page.
• IL: Illinois, the neighbor across the Mississippi River. See the Illinois abbreviation.
• IN: Indiana, not Iowa. See the Indiana abbreviation.

A quick memory trick: Iowa is the only one whose code uses its first and last letters, I and A.

Examples in sentences

• "Ship the order to Dubuque, IA 52001."
• "She grew up in Sioux City, Iowa, and moved east for college."
• "State: IA" on a driver's form or a job application.
• "Iowa farmers planted early this spring." No abbreviation in running text.
• In a table of sales by state, the row label can be IA to keep columns narrow.

Notice that only the address, the form box and the table use the code. Every full sentence spells the state out.

A little background on the codes

Iowa became a state in 1846. For more than a century, people wrote it out or used informal short forms. Two-letter codes came in the same decade that ZIP codes began, the 1960s, because the Postal Service wanted short, fixed codes that fit on one line with a city name and a ZIP.

IA has been Iowa's code ever since. It is an abbreviation, not an acronym, because it is a clipped form of one word rather than the first letters of several words.