The Ohio abbreviation used on mail and forms is OH, a two-letter code from the US Postal Service. Type it as two capitals, no dot, as in "Dayton, OH 45402." Unlike most states, Ohio has no traditional abbreviation in everyday use. With only four letters, the name is already short, so writers simply spell it out.
That makes Ohio a state that is hard to get wrong. Use OH where a code is required and Ohio everywhere else, including news stories, school reports and letters.
Quick facts
Postal code
OHTraditional
None in common use; write OhioAP style
Always Ohio, even in datelinesUsed in
Addresses, shipping labels, forms, data tablesCapital city
ColumbusZIP codes start with
43, 44 or 45Not to be confused with
OK (Oklahoma), OR (Oregon)
Choosing between OH and Ohio
| You are writing | Use | Example |
|---|---|---|
| An envelope or package | OH | Toledo, OH 43604 |
| A drop down menu or form box | OH | State: OH |
| A spreadsheet column of states | OH | OH, PA, MI, IN |
| A sentence, essay or email | Ohio | The river forms Ohio's southern border. |
| A news dateline | Ohio | CLEVELAND, Ohio |
The rule of thumb: if a machine or a narrow column will read it, use OH. If it lands inside a sentence for someone to read, write Ohio. The state abbreviations page has the same advice for the other states.
Why Ohio has no traditional abbreviation
Before the postal codes, writers shortened long state names by clipping them: Calif., Penn., Mass. Short names gave them nothing to gain. Ohio is four letters, and cutting it to two or three saves almost no space while making it harder to read.
Ohio shares this trait with Alaska, Hawaii, Idaho, Iowa, Maine, Texas and Utah, the eight states that AP style never abbreviates.
The Ohio abbreviation in AP style
AP news style writes out state names inside articles, so most states keep a short form only for datelines. Ohio does not even have that. A wire story from the state capital opens with "COLUMBUS, Ohio," with the full name in place of an abbreviation.
Newspaper photo caption: "Fans gather outside the stadium in Cincinnati, Ohio, before the game." No abbreviation appears, because the house style never shortens Ohio.
The postal code OH would look out of place in that caption. Save it for addresses.
OH, OK and OR: codes that get mixed up
Three states start with O, and quick typists confuse their codes.
- OH is Ohio. The H comes from the last letter.
- OK is Oklahoma. It is also an everyday word, so it is easy to mistype in a form.
- OR is Oregon, on the far side of the country.
Another slip is reading OH as the word "oh." On a form the context makes it clear, but in a text message "heading to OH" and "heading to oh" look odd either way, so write Ohio in casual messages. Ohio's neighbors also have their own pages, including the Michigan abbreviation and the Pennsylvania abbreviation.
Example lines with OH and Ohio
- "Return address: 88 Elm St., Akron, OH 44308."
- "Billing state: OH."
- "The team plays three road games in Ohio this month."
- "Ohio became the 17th state in 1803."
- "She lives in Columbus, Ohio, near the university."
Ohio ZIP codes begin with 43, 44 or 45. If an Ohio address carries a ZIP code that starts with another number, it is probably a typo.
Tips for writing the OH state abbreviation
- Two capitals, no period, no space: OH.
- Do not write Oh. or O.H.; neither is a recognized form.
- Spell out Ohio in any sentence, title or heading.
- In a list of cities with states, either use codes for all of them or full names for all of them.
Curious about why postal codes are not really acronyms? Our guide to acronyms vs abbreviations explains the difference.
Questions people ask
What is the abbreviation for Ohio?
The abbreviation for Ohio is OH, the USPS postal code. There is no traditional abbreviation in common use, so in writing the name is spelled out.
Is Ohio abbreviated OH or OI?
It is OH. OI is not a state code, and using it can confuse sorting machines and online forms.
Does AP style abbreviate Ohio?
No. AP style always writes Ohio in full, in datelines and in the body of a story, because the name is already short.
Is it O.H. with periods?
No. Postal codes are bare capital pairs. Adding dots, as in O.H., is not correct.