The Wyoming abbreviation you need most often is WY, the short code that the US Postal Service gives the state. Use it on envelopes, package labels, web forms and any box that asks for a state. The older written abbreviation is Wyo., four characters ending in a dot, still seen at the top of news stories and in some formal documents.
In an ordinary sentence, most style guides prefer the full name. "She moved to Wyoming" reads better than either short form. The trick is knowing which setting calls for which version.
Quick facts
Postal code
WY (no period)Traditional
Wyo.AP style
Wyo. in datelines, Wyoming in body textCapital
CheyenneStatehood
1890, the 44th stateOften confused with
WI (Wisconsin), WA (Washington), WV (West Virginia)
Every Wyoming abbreviation, side by side
| Form | Use it for | Sample |
|---|---|---|
| WY | Addresses, forms, databases, shipping | Cheyenne, WY 82001 |
| Wyo. | News datelines, older reference style | LARAMIE, Wyo. (start of a news story) |
| Wyoming | Running text in almost every style | The family drove across Wyoming. |
WY is two capital letters, nothing else. Wyo. has one capital, three lowercase letters and a period at the end. Never write "Wy." or "WYO"; neither is a standard form.
When the postal code WY is the right choice
The two-letter codes were introduced so that machines could read addresses quickly and so that city, state and ZIP could fit on one line. That is still their job. Use WY when:
- You address an envelope or package.
- A form has a state box or a drop-down list.
- You fill in a spreadsheet or a database column for state.
- Space is tight, as in a table or a chart label.
Return address on a wedding thank you note:
The Ortega Family
412 Prairie View Rd
Casper WY 82601
The post office prefers capitals and no commas, though a comma after the city is also fine.
Wyo. in news writing and AP style
The traditional abbreviation predates the postal codes. Newspapers kept a version of it. AP style writes out every state name inside the text of an article, but a dateline at the top uses the short form, so a report from the capital starts "CHEYENNE, Wyo." Some older books, legal citations and library records also use Wyo.
With no style guide to follow, as in a class essay or an office memo, spell out Wyoming in sentences and save WY for addresses. That keeps things clear.
WY and the W codes people mix up
Four states start with W, and their codes look alike at a glance:
| Code | State | Memory hook |
|---|---|---|
| WY | Wyoming | The Y matches the y in Wyoming |
| WI | Wisconsin | The I follows the W in Wisconsin |
| WA | Washington | The A follows the W in Washington |
| WV | West Virginia | One letter from each word |
A mistyped code can route a parcel to a state far from Cheyenne, so check it twice. The full list is on the state abbreviations page, and the Wisconsin abbreviation and Washington abbreviation pages cover the two most common mix-ups.
A few facts that come with the name
Wyoming became the 44th state in 1890, and Cheyenne is its capital. It has the smallest population of any state, spread over wide plains and mountain ranges. Its nickname, the Equality State, comes from its early lead on voting rights: as a territory in 1869, it gave women the right to vote, well before the rest of the country.
Neighbors include Montana to the north and Colorado and Utah to the south. If you are writing addresses for a road trip, the Montana abbreviation and Colorado abbreviation pages may help.
Quick tips for writing Wyoming
- Mail and forms: WY.
- News dateline: Wyo.
- Sentences: Wyoming.
- Do not add a period to WY.
- Do not invent forms like Wy. or Wyom.
To see why postal codes skip periods while older forms keep them, read how to abbreviate.
Questions people ask
What is the postal abbreviation for Wyoming?
It is WY. The US Postal Service uses this code for every Wyoming address, and it never takes a period.
Is Wyoming WY or WI?
Wyoming is WY. WI is Wisconsin, a different state in the Midwest.
What is the old abbreviation for Wyoming?
Wyo. is the older form. Writers used it long before ZIP codes, and AP datelines keep it today.
Should I write WY or Wyoming in an essay?
Write Wyoming in full inside sentences. Use WY only in addresses, tables or forms.
Does WY need a period?
No. Postal codes never take periods. Only the traditional form, Wyo., ends with one.